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<strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> 14<br />
(updated August 2013)<br />
Pesticide products are listed in alphabetical order and not by effectiveness. This is not a complete list <strong>of</strong> all product<br />
formulations that may be registered for use on a particular crop. Product registrations and labels may change. Read the<br />
LABEL CAREFULLY before applying any pest control product. is used to indicate products that are classed as danger<br />
poison.<br />
For commercial tree fruit see also the Ministry’s Tree Fruit Production Guide. For landscape plants see also the Home &<br />
Garden Pest Management Guide for British Columbia.<br />
Pest Description<br />
ABIES – FIR<br />
Diseases:<br />
Current Season Needle Necrosis: This<br />
physiological disorder affects grand and<br />
noble firs. Symptoms appear in late June to<br />
early July on new growth and can differ<br />
greatly from one tree to the other. Portions <strong>of</strong><br />
the needles turn yellow, then tan, and finally<br />
darken to a reddish brown. In some cases,<br />
entire needles change colour followed by<br />
severe needle loss.<br />
Grovesiella Canker (Grovesiella abieticola): Flagging<br />
and dieback <strong>of</strong> lower branches to yellowing,<br />
stunting and death <strong>of</strong> trees. Needles yellow<br />
and drop. Cankers <strong>of</strong>ten appear at the base <strong>of</strong><br />
the trunk. The infected branch or trunk swells<br />
above the canker, which appears as an<br />
elongated depression. Shasta and white pine<br />
are more susceptible than grand or noble fir.<br />
Interior Needle Blight (mainly associated with<br />
Mycosphaerella spp.): Noble and grand fir.<br />
Random browning <strong>of</strong> older needles on lower<br />
branches in late summer/fall. Needles remain<br />
attached to the branch and do not shed as<br />
with physiological stress. Black fungal<br />
fruiting bodies appear on underside <strong>of</strong><br />
needles in spring.<br />
Needle Casts; Foliar and Twig Blights (Lirula spp.,<br />
Lophodermium spp. and Rhizosphaera spp.):<br />
Needles turn brown or yellow and drop, and<br />
twigs dieback. Black fungal fruiting bodies<br />
can be found on dying needles and twigs.<br />
Phaeocrytopus nudus is a common secondary<br />
saprophyte on dead twigs and needles.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Foliar application <strong>of</strong> calcium<br />
chloride during shoot elongation in<br />
spring can reduce incidence, but is<br />
<strong>of</strong>ten phytotoxic, so not generally<br />
recommended.<br />
BANNER MAXX: 35 mL (for use<br />
on Christmas trees only)<br />
COPPER SPRAY 50: 400 g<br />
FLINT 50WG: 210g/ha<br />
Apply when new growth starts in<br />
spring and repeat during<br />
prolonged rainy periods.<br />
Lophodermium Needlecast:<br />
Daconil 2787F: 2.4-4.8 L/ha<br />
Bravo Ultrex 90 SDG: 1.3-2.7 kg/ha<br />
Daconil Ultrex: 1.45-2.9 kg/ha<br />
Cultural<br />
Management<br />
The cause and control <strong>of</strong> this<br />
disorder is unknown. It<br />
occurs in open fields, but not<br />
in partially shaded<br />
situations.<br />
Trees with canker infections<br />
should be removed and<br />
burned. Do not put new<br />
plantings close to older<br />
diseased trees.<br />
Improve air circulation by<br />
weed control and pruning <strong>of</strong><br />
lower branches.<br />
Needle cast and blight fungi<br />
on fir are usually weak<br />
pathogens or secondary<br />
invaders following<br />
environmental damage.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 1
Pest Description<br />
Phytophthora Root Rot and Shoot Blight<br />
(Phytophthora spp.): Death <strong>of</strong> seedlings;<br />
browning and flagging <strong>of</strong> lower branches on<br />
older trees; stunting and sunken cankers on<br />
stems or on trunk just above soil line. There is<br />
swelling above the canker and wood is stained<br />
brown under the bark, unlike Grovesiella. Trees<br />
are usually affected within 3-4 years <strong>of</strong><br />
planting and <strong>of</strong>ten in pockets or groups.<br />
Rusts:<br />
Fir-Fern Rust (Urediniopsis spp.)<br />
Fir-Bracken Rust (Urediniopsis spp.)<br />
Fir-Fireweed Rust (Pucciniastrum spp.)<br />
Fir-Blueberry Rust (Pucciniastrum spp.)<br />
Fir-Willow Rust (Melampsora sp.)<br />
Fir-Broom Rust (Melampsorella spp.)<br />
White or yellow, cylindrical fungal structures<br />
called “aecia” appear on the underside <strong>of</strong><br />
needles. Alternate hosts (fern, fireweed-<br />
Epilobium spp. and willow) have yellow leaf<br />
spots. Severe infestations can cause needle<br />
drop, growth loss or death <strong>of</strong> trees.<br />
Scleroderris Canker (Gremmeniella abietina): Does<br />
not occur in BC. Causes shoot blight and<br />
cankers on pines and balsam fir in Eastern<br />
Canada.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
See General Disease Management:<br />
Root Rots Caused by Phytophthora<br />
and Pythium, Chapter 9.<br />
Cultural<br />
Management<br />
Do not plant Abies spp. on<br />
poorly drained soils.<br />
Remove alternate hosts<br />
within 300 m <strong>of</strong> fir. Cool,<br />
moist spring weather<br />
promotes infections.<br />
Seedling Blight (Sirococcus conigenus): See under PICEA - SPRUCE and General Disease Management: Sirococcus Blight,<br />
Chapter 9.<br />
Insects:<br />
Balsam Gall Midge (Paradiplosis tumifex): The adult<br />
midge appears when fir buds are developing.<br />
The female lays eggs in the opening buds. The<br />
larva feeds at the base <strong>of</strong> a needle, initiating the<br />
growth <strong>of</strong> gall tissue that will eventually enclose<br />
the larva. Galls are formed on current season<br />
needles. Infested needles yellow and abscise in<br />
the fall. The larvae overwinter in the soil.<br />
Balsam Woolly Adelgid (Adelges piceae): Branches<br />
and tips become swollen, which results in a<br />
“bird-claw” appearance. White woolly masses<br />
appear on bark. Most severe damage on Fraser<br />
and alpine fir.<br />
ACER - MAPLE<br />
Diseases:<br />
Anthracnose (Kabatiella apocrypta and Discula spp.<br />
(Apiognomonia)): Brown to white irregular<br />
blotches appear on the leaves. Twigs dieback.<br />
The causal fungus overwinters on twig cankers<br />
from which spores are splashed when hit by<br />
rain or irrigation water.<br />
MOVENTO 240 SC: 585 mL/ha<br />
BANNER MAXX: 28 mL<br />
Apply every 14 days. Do not<br />
apply more than 4 times per year.<br />
All Abies must be grown<br />
under permit. See British<br />
Columbia Plant Protection<br />
Regulations, Chapter 2.<br />
Remove dead and damaged<br />
twigs and those with visible<br />
cankers to reduce inoculum.<br />
Minimize sprinkler irrigation<br />
or schedule applications so<br />
the foliage has opportunity<br />
to dry <strong>of</strong>f quickly. Rake and<br />
burn fallen leaves.<br />
2 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
Infection occurs in cool, wet weather in spring<br />
and fall. Recent research in Oregon suggests<br />
that most infections on maple occur in the fall.<br />
Cinnamon Canker or Coral Spot Canker (Nectria<br />
cinnabarina): Orange-red or pink-coral coloured<br />
fungal “cushions” appear on dead or dying<br />
branches. This is a weak pathogen or saprophyte<br />
which usually affects branches killed or<br />
damaged by other factors, such as winter injury.<br />
Leaf Scorch (drought and Xyella fastidiosa bacterium):<br />
Browning and withering <strong>of</strong> leaves affecting the<br />
margins first and the veins last is common on<br />
red and lace leaf varieties <strong>of</strong> A. palmatum. It is<br />
usually caused by heat and drought. A<br />
bacterium called Xyella can also contribute to<br />
leaf scorch on landscape trees. Xyella has been<br />
found on Vancouver Island.<br />
Nectria Canker (Nectria galligena): Causes blistered<br />
bark and sunken, girdling cankers on twigs,<br />
limbs and trunks. Leaves and branches dieback<br />
above the cankered area. Edges <strong>of</strong> cankers<br />
become rolled and swollen in the second year<br />
after infection. Infection is through pruning or<br />
cutting wounds or new buds. Bright red fungal<br />
structures (perithecia) may be seen in fall at the<br />
edge <strong>of</strong> cankers.<br />
Tar Spot (Rhytisma acerinum): Causes circular black<br />
spots on the leaves in late summer <strong>of</strong> Norway,<br />
red, silver and sugar maples. The pathogen<br />
overwinters on fallen leaves. Spores spread from<br />
the soil to young leaves by wind or rain splash.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
See General Disease Management:<br />
Bacterial Blight, Chapter 9.<br />
There is no chemical control for<br />
the bacterial disease.<br />
BANNER MAXX: 28 mL<br />
COMPASS 50WG: 14-21 g<br />
Wilt (Verticillium dahliae): See General Disease Management: Verticillium Wilt, Chapter 9.<br />
Insects and Mites:<br />
Boxelder Bug (Leptocoris rubrolineatus): The adult bug<br />
is 1.2 cm long, black with red stripes on the<br />
mid-section <strong>of</strong> the body and red veins on<br />
wings. Nymphs are bright red. Associated with<br />
key-bearing boxelder trees. Occasionally<br />
hibernate in houses.<br />
Forest Tent Caterpillar (Malacosoma disstria):<br />
Caterpillars feed on leaves in summer. In the<br />
Interior, they occur in the spring and do not<br />
make tents.<br />
SEVIN T&O: 230-350 mL<br />
Spray when insects are first seen.<br />
See General Insect and Mite<br />
Management: Tent Caterpillars and<br />
Skeletonizers, Chapter 11.<br />
Maple Bladder Gall Mite (Vasates quadripedes): It feeds ACECAP 97: Apply only if very<br />
on the undersides <strong>of</strong> maple leaves in the spring high populations <strong>of</strong> galls develop<br />
causing numerous galls or a red, fuzzy growth on foliage. For rate, see label or<br />
on the leaf tissue. The `gall’ eventually surrounds General Insect and Mite<br />
the mite. The mite exits the gall before leaf fall Management: Aphids, Chapter 11.<br />
and overwinters at the base <strong>of</strong> the buds. There<br />
are several generations per year.<br />
Cultural<br />
Management<br />
All maples except sugar<br />
maple (A. saccharum) are<br />
susceptible. A. palmatum<br />
‘Sanga Kaku’ and ‘Oshi Beni’<br />
are highly susceptible.<br />
Prune out affected branches<br />
and twigs. Protect young<br />
trees from winter injury.<br />
Avoid planting susceptible<br />
varieties in areas where they<br />
will be exposed to hot, dry<br />
winds. Plants in containers<br />
or in well-drained soil must<br />
be kept well-watered during<br />
hot weather.<br />
Prune out dead and diseased<br />
twigs promptly, disinfect<br />
pruners between trees. Prune<br />
only during dry weather. Do<br />
not leave long stubs when<br />
removing the rootstock top<br />
growth after the scion has<br />
started to grow.<br />
Collect and dispose <strong>of</strong> fallen<br />
leaves and prune trees to<br />
improve air circulation in the<br />
crown.<br />
Do not plant maples in soil<br />
where potatoes, berries or<br />
Verticillium-infected trees<br />
have been grown.<br />
Remove overwintering egg<br />
masses encircling twigs.<br />
During the growing season,<br />
prune <strong>of</strong>f branches with tents.<br />
These mites do not damage<br />
landscape trees but can be<br />
unsightly on nursery stock.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 3
Pest Description<br />
AESCULUS - HORSE CHESTNUT<br />
Diseases:<br />
Leaf Blotch (Guignardia aesculi): Reddish-brown leaf<br />
spots and blotches with bright yellow margins<br />
appear in summer. Very similar to scorch (see<br />
below) but with small black fungal fruiting<br />
bodies (pycnidia) in the centre <strong>of</strong> the spot.<br />
Pycnidia develop early in June and release<br />
spores that initiate secondary infection cycles<br />
throughout the summer in wet weather.<br />
Leaf Scorch (environmental): Large, reddish-brown<br />
blotches with bright yellow haloes appear<br />
during hot weather in summer, <strong>of</strong>ten on<br />
margins <strong>of</strong> leaves. No black fungal fruiting<br />
bodies are present, unlike Guignardia blotch (see<br />
above).<br />
AMELANCHIER - SASKATOON<br />
Diseases:<br />
Black Leaf and Witches’ Broom (Apiosporina collinsii):<br />
Typical “Witches’ broom” symptoms are on<br />
new growth. Suckers are infected. Infected<br />
leaves roll downward and become covered<br />
with a black mould on the upper surface and a<br />
grey felt-like mat on the lower surface. It has<br />
been found occasionally on fruit in the Interior.<br />
Leaf and Berry Spot (Entomosporium mespili): Small,<br />
angular leaf spots on foliage and fruit. Worse<br />
under high moisture and warm temperatures.<br />
Petioles, stems and flower stalks may also be<br />
infected causing leaf and fruit drop.<br />
Monilinia Brown Rot and Mummyberry (Monilinia<br />
amelacchieris): Brown spots on leaves and fruit,<br />
mummified fruit. Favoured by humid weather<br />
and insect damage. Can also cause blossom<br />
blight and twig infections.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Nursery or newly-transplanted<br />
trees:<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply at bud break and repeat<br />
every 7-14 days as needed.<br />
FUNGINEX DC: 300 mL. Apply<br />
once between bud break and<br />
white tip stage; 60 days to<br />
harvest.<br />
KUMULUS DF: 7.5 kg/ha. Apply<br />
at flower bud break and 10-14<br />
day intervals.<br />
TOPAS 250E: 500 mL/ha; apply 3<br />
times a year at white tip, petal<br />
drop and green fruit stage.<br />
No fungicides are specifically<br />
registered for this disease, but<br />
application <strong>of</strong> TOPAS 250E for<br />
leaf and berry spot (above)<br />
should help to control Monilina<br />
rot also.<br />
Cultural<br />
Management<br />
Rake and destroy fallen<br />
leaves where the fungus<br />
overwinters. Established<br />
landscape trees may be<br />
infected every year without<br />
serious injury or decline.<br />
Fungicide applications are<br />
not usually necessary or<br />
practical on large, landscape<br />
trees.<br />
May appear on susceptible<br />
trees every year, but is rarely<br />
damaging in the long term.<br />
Good growing conditions<br />
and proper watering may<br />
reduce the severity <strong>of</strong><br />
symptoms.<br />
Remove and destroy all<br />
infected seedlings and<br />
transplants. Prune shoots 10-<br />
20 cm below the infected<br />
area on mature plants,<br />
usually after leaf drop in the<br />
fall. Remove and burn all<br />
infected leaves and<br />
prunings, and any plants<br />
with crown infections.<br />
Increase air circulation and<br />
reduce leaf wetness by<br />
spacing nursery plants,<br />
controlling weeds, and<br />
avoiding overhead<br />
irrigation. Remove and burn,<br />
bury or compost fallen<br />
leaves if severe disease; or<br />
disc under in larger<br />
orchards. Prune out lower<br />
branches in orchards.<br />
Remove and burn, bury or<br />
compost mummified berries<br />
and fallen leaves.<br />
Powdery Mildew (Microsphaera podosphaera or Erysiphe spp.): See General Disease Management: Powdery Mildew, Chapter 9.<br />
4 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Rusts: Fungal fruiting bodies called “aecia” occur in<br />
yellow-brown leaf spots. Leaf drop, swelling <strong>of</strong><br />
infected petioles, and mummification <strong>of</strong> fruit are<br />
common symptoms. The alternate host (juniper)<br />
is required for infection to recur each year.<br />
Common rusts (Gymnosporangium spp.) that<br />
produce “aecia” on Amelanchier in W. Canada:<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
See General Disease Management:<br />
Rusts, Chapter 9.<br />
Clavariform Rust (Gymnosporangium clavariiforme): Yellow-brown leaf spot; fruit<br />
mummification. Common in Coastal BC. Aecia also occur on Crataegus (hawthorn)<br />
and other Rosaceae. Alternate hosts are in Juniperus Sect. Oxycedrus.<br />
Inconspicuous Juniper Rust (G. inconspicuum): Swelling <strong>of</strong> petioles;<br />
mummification <strong>of</strong> fruit. Occasional in Southern Interior only. Aecial hosts are<br />
Amelanchier and hawthorn. Alternate hosts are Juniperus Sect. Sabina.<br />
Juniper Broom Rust (G. nidus-avis): Common in Southern Interior. Other aecial<br />
hosts are quince and mountain ash. Alternate hosts are in Juniperus Sect. Sabina.<br />
Nelson’s Juniper Rust (G. nelsonii): Yellow leaf spot. Common in Southern Interior.<br />
Aecia on Amelanchier only. Alternate hosts are in Juniperus Sect. Sabina.<br />
Quince Rust (G. clavipes): Swelling <strong>of</strong> petioles; mummification <strong>of</strong> fruit. Not<br />
common in BC. Aecia also occur on many other Rosaceae species including quince,<br />
pear, apple, cotoneaster and hawthorn. Alternate hosts are in Juniperus.<br />
ANDROMEDA POLIFOLIA - BOG ROSEMARY<br />
Diseases:<br />
Red Leaf Spot (Exobasidium vaccinii): Red circular<br />
spots appear on upper side <strong>of</strong> leaves followed<br />
by defoliation. Symptoms usually appear in the<br />
early spring, although infection probably<br />
occurred during the previous fall/winter rains.<br />
ARCTOSTAPHYLOS - KINNIKINNICK<br />
Diseases:<br />
Root Rot (Pythium/Phytophthora spp.): S<strong>of</strong>t, brown<br />
roots on container plants. Basal rot <strong>of</strong> cuttings<br />
and poor rooting.<br />
AZALEA and RHODODENDRON<br />
Diseases:<br />
Cylindrocladium Blight and Root Rot<br />
(Cylindrocladium scoparium): The pathogen<br />
attacks a broad range <strong>of</strong> ornamentals, causing<br />
leaf spots, stem cankers, root rot and wilt. It is<br />
spread in soil and water, and by wind. Disease<br />
is favoured by high humidity and high<br />
temperature. It overwinters as microsclerotia in<br />
soil and infected plant tissue.<br />
Damping Off/Basal Rot <strong>of</strong> Cuttings<br />
(Pythium/Phytophthora spp. and other fungi):<br />
See also Root Rot, Wilt and Foliar Blight, below.<br />
Leaf Burn (Environmental): Leaves become brown<br />
then grey to white. Margins and interveinal<br />
areas are normally affected first. Leaf burn may<br />
be due to summer sunburn, winter desiccation<br />
or salt injury.<br />
Cultural<br />
Management<br />
Remove the juniper hosts<br />
listed below from within 2<br />
km <strong>of</strong> Amelanchier plantings.<br />
Remove Juniperus communis.<br />
Remove J. scopulorum.<br />
Remove J. horizontalis and<br />
J. scopulorum.<br />
Remove J. horizontalis and<br />
J. scopulorum.<br />
Remove all junipers from<br />
within 2 km <strong>of</strong> Amelanchier<br />
plantings.<br />
Overwinter container stock in<br />
polyhouses to help prevent<br />
disease spread; avoid overhead<br />
watering and reduce humidity<br />
in greenhouses.<br />
See General Disease Management: Damping Off and Stem Rot <strong>of</strong><br />
Cuttings and Root Rots Caused by Phytophthora and Pythium,<br />
Chapter 9.<br />
PHYTON 27: 125-275 mL<br />
See General Disease Management: Damping Off and Stem Rot <strong>of</strong><br />
Cuttings, Chapter 9.<br />
Grow sun-sensitive varieties<br />
in partial shade, and wintersensitive<br />
varieties in<br />
sheltered locations. Avoid<br />
salt injury from overfeeding.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 5
Pest Description<br />
Leaf Gall (Exobasidium vaccinii): This fungus<br />
overwinters on azalea bark and bud scales,<br />
infecting opening buds in spring. Leaves<br />
become fleshy, thickened, and covered in a<br />
white bloom <strong>of</strong> spores.<br />
Leaf Spots (Phyllosticta, Colletotrichum spp. and other<br />
fungi): These fungi are usually weak pathogens<br />
that infect winter or sun-damaged leaves. Spots<br />
and blotches are dark brown, zonate and may<br />
cover half the leaf area. Black fungal fruiting<br />
bodies are <strong>of</strong>ten present in the spots in humid<br />
weather.<br />
Lime-induced Chlorosis (Iron Deficiency): Leaves<br />
yellow between the veins, from margins<br />
inward. Veins remain green.<br />
Powdery Mildew (Microsphaera spp.): Large brown<br />
areas or faint yellow spots may appear on<br />
leaves in early spring. White powdery fungal<br />
growth may be on the underside <strong>of</strong> these areas.<br />
Root Rot, Wilt and Foliar Blight (Phytophthora spp.):<br />
Plants wilt and leaves curl and droop. Roots are<br />
brown and s<strong>of</strong>t, sometimes only on one side <strong>of</strong><br />
the plant. The rot may extend into the crown,<br />
where the advancing discolouration shows a<br />
distinct line with healthy tissue. Leaf and stem<br />
blight may occur without root rot. Symptoms<br />
are blackening <strong>of</strong> leaves, stems and petioles.<br />
Rust (Chrysomyxa spp.): Rust first appears as yellow<br />
spots on the upper leaf surface and brown to<br />
purple spots on the lower surface. Blisters form<br />
on the lower surface, which rupture to expose<br />
orange-red pustules. Several generations can<br />
occur in one growing season. It will overwinter<br />
on rhododendron and azalea and cause new<br />
infections each spring. Spruce may be an<br />
alternate host for some <strong>of</strong> these rust species.<br />
Tissue Proliferation (Genetic or Physiological<br />
Disorder): A large gall occurs at the base <strong>of</strong><br />
rhododendron stems that resembles crown gall<br />
infection. Small shoots <strong>of</strong>ten develop from the<br />
gall. Galls may also be present on stems.<br />
Growth is not usually affected, but large galls<br />
may cause gradual decline <strong>of</strong> the plant and<br />
stems may break <strong>of</strong>f at gall sites.<br />
Insects:<br />
Lace Bugs (Stephanitis pyrioides): Small white spots<br />
appear in a dense mass on leaves in early<br />
spring. Damage resembles mite injury. Tiny<br />
lace bug nymphs can be seen on the underside<br />
<strong>of</strong> damaged leaves.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Commercial nurseries:<br />
Application <strong>of</strong> DACONIL 2787<br />
for foliar Phytophthora blight (see<br />
below) should provide some<br />
control <strong>of</strong> these diseases also.<br />
(See Root Rot, Wilt and Foliar<br />
Blight, below.)<br />
Apply an iron chelate foliar<br />
fertilizer spray or soil<br />
application.<br />
Cultural<br />
Management<br />
Do not overhead irrigate<br />
where leaf gall has been a<br />
problem. Remove and destroy<br />
leaves with galls as they<br />
appear. Reduce greenhouse<br />
humidity.<br />
Collect and compost, bury or<br />
burn affected leaves and<br />
fallen leaves. Provide good<br />
plant care and proper<br />
nutrition. Plant sun-sensitive<br />
varieties in shaded areas and<br />
protect frost-sensitive<br />
varieties from winter injury.<br />
If soil is high in lime,<br />
incorporate organic matter or<br />
a sulphur-containing<br />
fertilizer. Work soil shallowly<br />
to avoid damaging feeder<br />
roots close to surface.<br />
See General Disease Management: Powdery Mildew, Chapter 9.<br />
Foliar blight:<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
May discolour blooms.<br />
Soil drench:<br />
TRUBAN 30WP: 0.6-0.9 kg/100 m 2<br />
TRUBAN 25EC: 115-240 mL/40 m 2<br />
SULPHUR (DOMESTIC): 0.4 - 0.9<br />
% or other formulations. See label<br />
for rates and application.<br />
Use disease-free stock. Place<br />
containers on coarse, welldrained<br />
beds. Avoid heavy,<br />
wet soils for field growing.<br />
See Appendix H for a list <strong>of</strong><br />
Rhododendron species and<br />
varieties that are resistant to<br />
root rot.<br />
Plants growing in crowded,<br />
damp or shady locations are<br />
more likely to become<br />
infected. Collect and destroy<br />
infected leaves. See General<br />
Disease Management: Rusts,<br />
Chapter 9.<br />
Provide good growing<br />
conditions. Rogue out<br />
affected plants if desired.<br />
See General Insect and Mite Management: Lace Bugs, Chapter 11.<br />
6 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Mealybugs: These scale-like insects have a s<strong>of</strong>t scale<br />
that is covered in white, powdery wax. They<br />
feed on the sap <strong>of</strong> plants and produce<br />
honeydew. The honeydew attracts ants and<br />
<strong>of</strong>ten leads to the growth <strong>of</strong> sooty mold.<br />
Affected plants appear unthrifty and yellow.<br />
Root Weevils: Larvae girdle roots and crown tissue,<br />
and the adults notch leaf margins.<br />
BERBERIS – BARBERRY<br />
Diseases:<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Leaf Spot/Anthracnose (Phyllosticta spp./Gloeosporium berberidis): See Mahonia.<br />
BETULA – BIRCH<br />
Diseases:<br />
Leaf Blister (Taphrina spp.): This fungal disease<br />
related to peach leaf curl causes red blisters and<br />
curling <strong>of</strong> leaves.<br />
Insects:<br />
Apple & Thorn Skeletonizer and Other Caterpillars:<br />
Caterpillars are about 12 mm long, yellowish to<br />
greenish with many black dots. They begin<br />
feeding on underside <strong>of</strong> leaves, later moving to<br />
upper surfaces. Silken webs are formed, curling<br />
the leaves. The feeding “skeletonizes” leaves.<br />
Birch Leafminer (Fenusa pusilla): The adult is a black<br />
sawfly (3 mm long) that lays eggs in young<br />
leaves. The white larvae mine the leaves, which<br />
turn brown. There are 2 generations per season.<br />
Bronze Birch Borer (Agrilus anxius): Usually attacks<br />
weak or injured trees. The adult is a 13 mm<br />
long, olive-bronze beetle. Adults appear in<br />
May-June and lay eggs in bark crevices. Larvae<br />
(grubs) up to 15 mm long, chew tunnels under<br />
the bark, girdling twigs and branches and<br />
causing the upper part <strong>of</strong> the tree or branch to<br />
dieback. Chlorotic leaves and sparse upper<br />
branches are the first symptoms. Lumpy bark<br />
and half-moon-shaped beetle exit holes can be<br />
found.<br />
BUXUS – BOXWOOD<br />
Diseases:<br />
Boxwood Blight (Cylindrocladium buxicola): It was first<br />
detected in North America in 2011. The<br />
pathogen is spread by wind-driven rain and<br />
splashing water. Symptoms include brown leaf<br />
spots, black streaks on stems, and rapid<br />
defoliation. Clusters <strong>of</strong> spores are produced by<br />
the white fungal growth (mycelium) on the<br />
underside <strong>of</strong> leaves under warm and humid<br />
conditions. It does not infect roots. It<br />
overwinters in the plant and leaf debris.<br />
Cultural<br />
Management<br />
unit area if indicated)<br />
See General Insect and Mite Management: Mealybugs, Chapter 11.<br />
See General Insect and Mite Management: Root Weevils, Chapter 11.<br />
Prune out infected leaves and<br />
twigs if practical and rake<br />
fallen leaves.<br />
See General Insect and Mite Management: Tent Caterpillars and<br />
Skeletonizers, Chapter 11.<br />
See General Insect and Mite Management: Leafminer/Needle Miners,<br />
Chapter 11.<br />
DURSBAN WSP: 44.8 g<br />
PRO DURSBAN TURF: 50 mL<br />
If insecticide treatment is<br />
necessary, make three<br />
applications at 2-3 week<br />
intervals during June and July<br />
to control adults before they lay<br />
eggs. Thorough coverage is<br />
important. Insecticides will not<br />
kill grubs under the bark.<br />
DACONIL 2787: 250 mL<br />
SWITCH 62.5: 100 g<br />
NOTE: These are emergency<br />
registrations that expire on<br />
December 31, 2013.<br />
Drought-stressed trees are<br />
more susceptible. Keep trees<br />
healthy to prevent borer<br />
invasion (e.g. provide with<br />
optimum fertilizer and water).<br />
Prune, burn or chip<br />
wilted/dead branches to<br />
destroy larvae in the wood.<br />
Appendix A ranks<br />
susceptibility <strong>of</strong> white-barked<br />
birch to birch borer.<br />
Inspect incoming plants for<br />
symptoms and isolate from<br />
existing boxwood stock for at<br />
least 3 weeks. Sanitize pruning<br />
tools and collect leaf debris. Do<br />
not plant new boxwoods into<br />
landscapes with mature<br />
boxwoods.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 7
Pest Description<br />
Volutella Leaf and Stem Blight (Pseudonectria<br />
rousseliana): Causes branch dieback and leaves<br />
on affected branches to yellow and then turn<br />
straw-tan in color. Diagnostic pink fungal<br />
spore-producing structures develop on the<br />
underside <strong>of</strong> affected leaves.<br />
Insects:<br />
Boxwood Leafminer (Monarthropalpus buxi):<br />
Leafminers overwinter in the larval stage in the<br />
leaves. In April they pupate in an orangecoloured<br />
casing and emerge as a gnat-like fly<br />
when Weigela begins to bloom. Eggs are laid in<br />
the current year’s foliage. Damage is from the<br />
larvae that hatch and feed within the leaves.<br />
Boxwood Psyllid (Psylla buxi): Eggs, orange in colour,<br />
overwinter between bud scales. Nymphs<br />
emerge when the buds open. Terminal leaves<br />
become cupped and protect the feeding insects.<br />
Adults, greenish jumping “plant lice”, appear<br />
in late spring.<br />
CALLUNA - HEATHER<br />
Diseases:<br />
Root Rot (Phytophthora spp.): Infection first occurs in<br />
fibrous roots, then spreads to the entire root<br />
system and crown. Individual branches<br />
dieback or yellow, followed by plant death.<br />
CAMELLIA<br />
Diseases:<br />
Botrytis Grey Mould (Botrytis cinerea): Flowers, buds,<br />
leaves and petioles brown and drop under high<br />
humidity. Dead plant parts are covered with a<br />
grey to brown, fuzzy mould.<br />
Bud Drop/Brown Petals (Environmental): Flower<br />
bud drop may occur if plants are located in<br />
sites exposed to cold, dry winds or summer<br />
heat. Bud drop can also be caused by low<br />
winter temperatures, over-watering or drought<br />
stress. Many older varieties are not winter<br />
hardy in BC and regularly drop flower buds.<br />
Bud drop will also occur if more buds develop<br />
than the plant can support. Brown petals result<br />
from spring frost damage to flower buds.<br />
Flower and Petal Blight (Ciborinia camellias<br />
(Sclerotinia camelleae)): Only flowers are<br />
infected. Small brown spots on petals later<br />
enlarge until the whole flower browns. Hard,<br />
brown to black fungal bodies (sclerotia)<br />
develop on the base <strong>of</strong> old infected flowers.<br />
These can survive in soil for several years.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Apply an insecticide as soon as<br />
growth starts in the spring. See<br />
General Insect and Mite<br />
Management: Leafminer / Needle<br />
Miners, Chapter 11.<br />
SEVIN T&O: 230-350 mL; spray<br />
when new growth begins, or<br />
when the insect or damage is<br />
first seen.<br />
Cultural Management<br />
Prune and dispose <strong>of</strong> dead<br />
branches and leaves in the<br />
crown. Maintain good air<br />
circulation to promote rapid<br />
drying <strong>of</strong> foliage.<br />
Gather and dispose <strong>of</strong> fallen<br />
leaves to reduce the number <strong>of</strong><br />
leafminers.<br />
For bed and container-grown plants, see General Disease<br />
Management: Root Rot Caused by Phytophthora and Pythium, Chapter<br />
9.<br />
For cutting propagation, see Damping Off and Basal Rot <strong>of</strong> Cuttings,<br />
Chapter 9.<br />
See General Disease Management: Botrytis Blight and Storage Moulds,<br />
Chapter 9.<br />
CAPTAN 50-WP: 200 g<br />
CAPTAN 80-WP: 125 g<br />
MAESTRO 80DF: 125 g<br />
Plant in sheltered areas in welldrained<br />
soils that have good<br />
organic matter content. To<br />
avoid frost damage, choose<br />
sites that do not receive early<br />
morning sun. Select hardy<br />
varieties. Water during hot, dry<br />
weather.<br />
Remove and destroy infected<br />
flowers. Rake and burn old<br />
leaves and infected flowers. Do<br />
not compost. Remove surface<br />
soil beneath heavily infected<br />
plants.<br />
8 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Insects:<br />
Mealybugs: These scale-like insects are covered in<br />
white, powdery wax. They feed on plant sap<br />
and produce honeydew, which attracts ants<br />
and leads to the growth <strong>of</strong> sooty mold.<br />
Affected plants appear unthrifty and yellow.<br />
Root Weevils: Both black vine and strawberry root<br />
weevils attack camellia. The adults feed on<br />
leaves; larvae on roots and the base <strong>of</strong> stems.<br />
CANNA LILY<br />
Diseases:<br />
Canna Yellow Mottle Virus (Badnavirus): It was<br />
detected in the Province in 2007. The<br />
symptoms include yellowing and mottling <strong>of</strong><br />
leaf veins. It is reported to only infect Canna<br />
lilies. It is spread by propagating from infected<br />
stock plants. Insects have not been shown to<br />
transmit this virus. Canna Mosaic Virus is also<br />
known to infect cannas in North America.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Cultural Management<br />
See General Insect and Mite Management: Mealybugs, Chapter 11.<br />
See General Insect and Mite Management: Root Weevils, Chapter 11.<br />
Remove and destroy infected<br />
plants. It is important to use<br />
virus free stock for production.<br />
CEDRUS - ATLAS CEDAR, DEODARCEDAR, CEDAR <strong>of</strong> LEBANON<br />
Diseases:<br />
Tipblight (environmental Injury plus Sirococcus and<br />
Sclerophoma spp. fungi): Twig tips dieback in<br />
early spring, <strong>of</strong>ten forming a “hook”. Damage<br />
can be extensive in years with warm winters<br />
and occasional frosts, and very wet springs.<br />
Both fungi have been found associated with the<br />
disease in the Pacific Northwest.<br />
CEANOTHUS<br />
Diseases:<br />
COPPER SPRAY 50: 400 g<br />
Apply when new growth starts<br />
in the spring and repeat 3-4<br />
times at 10 day intervals.<br />
Prune out infected twigs.<br />
Protect small trees from frost<br />
damage, if possible. The<br />
disease is much less severe in<br />
warm, dry springs.<br />
Basal Rot <strong>of</strong> Stem Cuttings (Pythium/Phytophthora spp. and other fungi): See General Disease Management: Damping Off<br />
and Stem Rot <strong>of</strong> Cuttings, Chapter 9.<br />
CHAMAECYPARIS - FALSE CYPRESS, YELLOW CEDAR, PORT-ORFORD<br />
CEDAR, LAWSON’S CYPRESS<br />
Diseases:<br />
Cypress Root Rot (Phytophthora lateralis primarily;<br />
also Phytophthora cinnamomi and other spp.):<br />
Roots <strong>of</strong> Lawson’s cypress become infected by<br />
Phytophthora during periods <strong>of</strong> high soil<br />
moisture or flooding. Infection moves into<br />
larger roots and finally into the base <strong>of</strong> the tree,<br />
causing a dark discolouration <strong>of</strong> the sapwood.<br />
Foliage begins to lose colour, turning<br />
completely brown within a few months. Large,<br />
healthy trees <strong>of</strong>ten die completely in one<br />
growing season once infection sets in.<br />
There is no effective fungicide<br />
treatment.<br />
Use Lawson’s cypress that is<br />
grafted onto a resistant<br />
rootstock. Chamaecyparis<br />
nootkatensis, C. pisifera and C.<br />
thyoides are resistant, but the<br />
graft union may not be longlived.<br />
In the landscape, do not plant<br />
Lawson’s cypress in areas<br />
subject to flooding. Replace<br />
dead trees with resistant<br />
species, such as Thuja plicata.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 9
Pest Description<br />
Foliar Blights (Kabatina thujae, Seiridium cardinale and<br />
Seiridium unicorne): Foliage on individual<br />
branches turns yellow, then brown to grey<br />
before shattering, eventually leaving large bare<br />
areas. Twig canker/dieback <strong>of</strong>ten occurs on<br />
new growth. These fungi also cause foliar<br />
blights on Thuja.<br />
Insects:<br />
Cypress Tip Moth (Argyresthia cupressella): See<br />
description under JUNIPERUS - JUNIPER.<br />
Juniper Scale (Carulaspis juniperi): This scale attacks<br />
cones, twigs and needles, causing bushes to<br />
turn greyish or yellow. Little new growth is<br />
produced and individual branches can die.<br />
Little honeydew is generated. The adult scale is<br />
grey and round. Crawlers appear in June.<br />
CLEMATIS<br />
Diseases:<br />
Botrytis Blight (Botrytis cinerea): Is a common cause<br />
<strong>of</strong> leaf blight on cuttings and greenhousegrown<br />
plants. It causes large, necrotic leaf<br />
lesions and dieback <strong>of</strong> petioles, <strong>of</strong>ten in<br />
conjunction with Ascochyta. A grey, fuzzy<br />
mould appears on dead tissue in humid<br />
conditions.<br />
Powdery Mildew (Erysiphe polygoni): Leaf and flower<br />
surfaces become covered with white powdery<br />
patches. Often occurs or is more severe on<br />
plants grown in shade.<br />
Stem Rot and Leaf Spot (“Clematis Wilt”) (Ascochyta<br />
clematidina): Attacks the roots, crown and stem<br />
near the soil line. Individual shoots wilt<br />
suddenly when stems are infected and girdled<br />
at the base. Wounds and warm, wet conditions<br />
favour infection. On leaves, small water-soaked<br />
spots with reddish margins enlarge to form<br />
brown circular/oval lesions. Black fungal<br />
fruiting bodies called “pycnidia” can<br />
sometimes be seen on infected tissue.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER SPRAY 50: 400 g<br />
If disease occurs every year,<br />
spray once prior to fall rains<br />
and every 14 days in spring to<br />
protect new growth.<br />
Cultural Management<br />
Avoid crowding and overhead<br />
watering. Avoid drought<br />
stress. Prune out affected<br />
branches below cankers.<br />
Sanitize pruning tools between<br />
cuts with 10% bleach, Lysol or<br />
other disinfectant.<br />
If damage is slight, infected<br />
foliage can be pruned out in<br />
mid-summer. See under<br />
JUNIPERUS – JUNIPER.<br />
See General Insect and Mite Management: Scales, Chapter 11.<br />
SENATOR 70WP: 65-85 g<br />
ROVRAL 50WP-WDG: 100 g<br />
Crop injury may occur. Test on a<br />
small area first before treating<br />
entire crop.<br />
See General Disease<br />
Management: Botrytis Blight<br />
and Storage Moulds, Chapter 9<br />
and Stem Rot and Leaf Spot<br />
(below).<br />
See General Disease Management: Powdery Mildew, Chapter 9.<br />
SENATOR 70WP: 65-85 g<br />
Use disease-free stock plants<br />
and maintain strict sanitation<br />
at propagation. Remove and<br />
destroy diseased plants.<br />
Reduce greenhouse humidity<br />
and overhead watering as<br />
much as possible. The disease<br />
is usually not a problem in the<br />
landscape, since the humidity<br />
is <strong>of</strong>ten too low for infection<br />
to occur.<br />
In Europe, there are reports <strong>of</strong><br />
a similar disease (“clematis<br />
wilt”) being caused by a<br />
Coniothyrium fungus. This<br />
disease is not present in North<br />
America.<br />
10 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
CORNUS - DOGWOOD<br />
Diseases:<br />
Anthracnose (Discula destructiva): Large wedgeshaped<br />
blotches appear on leaves in spring.<br />
Severe defoliation and twig cankers may result.<br />
If repeated for several years, the trees may<br />
weaken and eventually die. Cornus ‘Eddie’s<br />
White Wonder’, C. florida (Eastern Dogwood)<br />
and C. kousa (Japanese Dogwood) are more<br />
resistant than C. nuttallii (Western Dogwood).<br />
Crown Canker (Phytophthora cactorum): This soilborne<br />
organism infects the base <strong>of</strong> the trunk<br />
(crown) at the soil line, either through the roots<br />
or through injury to the bark. Infected trees lack<br />
vigour and slowly dieback. Wood beneath the<br />
bark <strong>of</strong> cankers is discoloured. The tree dies<br />
when the canker finally girdles the trunk.<br />
Phyllosticta Leaf Spot (Phyllosticta): The symptoms<br />
include circular to angular leaf spots with<br />
purple borders that develop in late summer<br />
and fall.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Nursery crops:<br />
BANNER MAXX: 28 g<br />
Apply every 14 days; no more<br />
than 4 applications per year.<br />
NOVA 40W: 34 g<br />
NOVA and BANNER have the<br />
same mode <strong>of</strong> action. To prevent<br />
disease resistance, do not<br />
alternate these products.<br />
Landscape:<br />
Dormant sprays with lime<br />
sulphur, or application <strong>of</strong><br />
fungicides as recommended for<br />
Septoria Leaf Spot (see below)<br />
may be helpful.<br />
There are no effective chemical controls.<br />
Cultural Management<br />
Do not grow or sell highly<br />
susceptible varieties. On small<br />
plants isolated from large<br />
infected trees, picking <strong>of</strong>f the<br />
first diseased leaves in spring<br />
may be beneficial. Raking and<br />
burning fallen leaves may<br />
significantly reduce<br />
overwintering inoculum. If<br />
severe disease continues,<br />
remove and replace with<br />
more resistant varieties.<br />
Management: Once this disease appears in a nursery, a<br />
conscientious clean-up and sanitation program is required. Avoid<br />
injury to the bark <strong>of</strong> established trees. Most infections <strong>of</strong> mature<br />
trees occur through wounds. Surgery <strong>of</strong> small cankers can<br />
prolong tree life. Clean out cankers during dry weather, paint<br />
with shellac, then with tree emulsion. Leave wounds exposed to<br />
air during summer. Do not cover with soil.<br />
Water early in morning to<br />
minimize the period <strong>of</strong> leaf<br />
wetness.<br />
Collect and dispose <strong>of</strong> leaves<br />
in the fall.<br />
Powdery Mildew (Microsphaera spp.): See General Disease Management: Powdery Mildew, Chapter 9. Information on the<br />
susceptibility <strong>of</strong> Cornus species to powdery mildew is included in Appendix C.<br />
Septoria Leaf Spot (Septoria spp.): Angular, greyish<br />
spots with dark purple margins appear on<br />
leaves. Black fungal fruiting bodies (pycnidia)<br />
may be seen in these spots in humid weather.<br />
Insects:<br />
Dogwood Sawfly (Macremphytus tarsatus): The larvae<br />
skeletonize the leaves <strong>of</strong> Cornus species, in<br />
particular C. racemosa and C. sericea. Look for<br />
the larvae on the underside <strong>of</strong> leaves. First<br />
instars are almost translucent yellow, while<br />
second instars appear to be covered with a<br />
chalky powder. The last instar is 2.5 cm long<br />
and is creamy-yellow with a black head and<br />
black spots. The larvae overwinter in decaying<br />
wood on the ground. Adult sawflies emerge<br />
the following spring.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply at early bloom. Repeat<br />
every 7-14 days as needed.<br />
NOVA 40W: 34 g<br />
See General Insect and Mite<br />
Management: Sawflies, Chapter 11.<br />
Rake up and burn, bury or<br />
compost fallen leaves.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 11
Pest Description<br />
CORYLUS - HAZELNUT<br />
Diseases:<br />
Bacterial Blight (Xanthomonas arboricola pv. corylina):<br />
New buds and shoots are blighted and oneand<br />
two-year-old twigs may have sunken<br />
purple-brown cankers. Trees may be girdled<br />
and killed at the base <strong>of</strong> the trunk (crown)<br />
during the first 10 years. Tissue under the bark<br />
<strong>of</strong> cankers and infected crowns is reddishbrown.<br />
Leaves may have small (2-3 mm),<br />
angular, water-soaked spots that turn reddishbrown.<br />
Roots are seldom infected.<br />
Eastern Filbert Blight (Anisogramma anomala):<br />
Infected branches show up from July to<br />
September when leaves turn brown but remain<br />
on the branch. Oblong, raised bumps (fungal<br />
fruiting bodies) in relatively straight rows<br />
begin to form under the bark <strong>of</strong> infected<br />
branches in June. By August the bumps are<br />
white, football shaped structures that have<br />
broken through the bark. These fungal<br />
structures turn black as they mature in the fall.<br />
COTONEASTER<br />
Diseases:<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
New growth wilts and turns black in the<br />
spring. The disease may occur at any time in<br />
propagation houses. It is common at the Coast.<br />
Dark Berry (Phytophthora cactorum): Berries turn<br />
brown to black and eventually shrivel up.<br />
Fire Blight (Erwinia amylovora): Flowers and new<br />
shoots wilt suddenly and turn brown. Dead<br />
leaves hang downward on affected twigs. This<br />
disease is rare at the Coast but common in the<br />
Interior.<br />
Scab (Venturia sp.): This fungus causes shedding <strong>of</strong><br />
blossoms, and dark, blotchy spots on leaves<br />
and fruit. Diseased leaves can be curled and<br />
distorted. New infections can occur whenever<br />
there is a moderate to prolonged rainy period<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER SPRAY 50: 300-900 g<br />
depending on tree size. Apply<br />
before fall rains, at ¾ leaf fall and<br />
before spring bud break.<br />
Maximum 3 applications per<br />
year.<br />
BRAVO 500: 6.72 L/ha<br />
COPPER SPRAY 50: 300-900 g.<br />
Apply from bud swell to bud<br />
break at 10-14 day intervals; up<br />
to 3 applications per year. Use<br />
low rate on small trees and high<br />
rate for large trees.<br />
FLINT 50WG: 140-280g/ha<br />
QUADRIS: 90 mL. From bud<br />
swell to bud break<br />
(approximately mid-March to<br />
mid-May), apply at 7-10 day<br />
intervals prior to disease<br />
development.<br />
Cultural Management<br />
See the Ministry’s Hazelnut<br />
Pest Management Guide.<br />
Protect trees from sunscald<br />
during the first few years. The<br />
bacterium infects through<br />
wounds, so disinfect pruners<br />
between cuts. Prune out<br />
infected branches 60-90 cm<br />
below lesions. ‘Barcelona’ is<br />
highly susceptible; ‘Du Chilly’<br />
is susceptible; ‘Daviana’ is<br />
intermediate and ‘Hall’s<br />
Giant’ is resistant.<br />
If you see suspicious<br />
symptoms, contact the<br />
Ministry’s Plant Pathologist in<br />
Abbotsford. The CFIA has<br />
initiated the process to<br />
deregulate the disease.<br />
‘Daviana’, ‘Butler’ and ‘Ennis’<br />
are highly susceptible;<br />
‘Barcelona’ is moderately<br />
susceptible; and ‘Willamette’<br />
and ‘Hall’s Giant’ are<br />
resistant. Ornamental<br />
contorted hazelnuts are also<br />
susceptible.<br />
See General Disease Management: Bacterial Blight/Canker, Chapter 9.<br />
Infection can be reduced by<br />
mulching to prevent soil<br />
water splashing and by<br />
planting in sunny locations<br />
with good air circulation.<br />
See General Disease Management: Fire Blight, Chapter 9.<br />
Copper sprays applied for fire<br />
blight may also give some<br />
control <strong>of</strong> scab.<br />
Rake and burn, bury or compost<br />
fallen leaves and fruit. A similar<br />
fungus causes scab on other<br />
Rosaceae. See under MALUS –<br />
APPLE and CRABAPPLE.<br />
12 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Insects:<br />
Cotoneaster Webworm (Athrips rancidella): The moth<br />
is blackish-brown with a 12 mm wingspan.<br />
Damage is caused in late May and June by<br />
chocolate-brown larvae, up to 12 mm long. The<br />
larvae skeletonize leaf surfaces, foraging from<br />
silken webs spun on foliage and twigs. Eggs<br />
are yellowish-red and laid in June and July.<br />
CRATAEGUS - HAWTHORN<br />
Diseases:<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
SEVIN T&O: 230-350 mL<br />
Apply when leaves are opening in<br />
May, and in late July and August.<br />
Crop injury may occur. Test on a<br />
small area first, before spraying<br />
the entire crop. Do not spray<br />
during bloom to avoid bee kills.<br />
Fire Blight (Erwinia amylovora): See General Disease Management: Fire Blight, Chapter 9.<br />
Leaf Spot (Fabrea Blight) (Diplocarpon mespili<br />
(Entomosporium mespili)): This is the most<br />
serious disease <strong>of</strong> Crataegus in Coastal BC. First<br />
symptoms are small, angular, reddish spots on<br />
the upper side <strong>of</strong> leaves in spring and early<br />
summer. Defoliation occurs in mid-summer.<br />
Rust (Gymnosporangium spp.): Crataegus is a common<br />
host <strong>of</strong> saskatoon rusts (see under<br />
AMELANCHIER - SASKATOON). Cedar rust<br />
is not common on Crataegus in BC except<br />
where a susceptible alternate host, such as<br />
Juniperus communis hibernica (Irish Juniper) is in<br />
close proximity. Cedar-apple rust is not known<br />
to occur in the province.<br />
Scab (Venturia inaequalis): Black leaf spots and scab on<br />
fruit.<br />
Insects:<br />
Leaf Skeletonizer (Psorosina hammondi): A yellowishgreen<br />
larva, up to 12 mm long, feeds on leaves,<br />
leaving only the veins and a thin layer <strong>of</strong> tissue<br />
behind.<br />
Rose Leafhopper (Edwardsiana rosae): The rose<br />
leafhopper is a slender, whitish-winged,<br />
sucking insect, about 3 mm long. Eggs are laid<br />
in the fall and hatch in spring. The nymphs are<br />
pale in colour and have red eyes. They suck<br />
juices out <strong>of</strong> the leaves creating a mottled<br />
effect. Premature defoliation can result.<br />
Sawfly (Pear Slug) (Caliroa cerasi): Adult is a shiny<br />
black fly with four wings. Black slug-like<br />
larvae skeletonize leaves in summer. There are<br />
two generations per season.<br />
Tent Caterpillar (Malacosoma spp.): Damage starts<br />
after buds burst.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Apply when leaves unfurl in spring<br />
and every 7-14 days in wet weather.<br />
Dormant:<br />
Application <strong>of</strong> lime sulphur may<br />
help in control.<br />
See General Disease Management:<br />
Rusts, Chapter 9.<br />
No fungicides are specifically<br />
registered for this disease on<br />
hawthorn. The fungicides<br />
applied for leaf spot (see above)<br />
should give some control.<br />
Cultural Management<br />
Remove infested leaves if<br />
damage is minor.<br />
See General Insect and Mite<br />
Management: Caterpillars and<br />
Moths, Chapter 11.<br />
Rake up and burn, bury or<br />
compost fallen leaves to<br />
remove the overwintering<br />
fungus.<br />
Avoid growing hawthorns<br />
close to junipers.<br />
Rake up and burn, bury or<br />
compost fallen leaves.<br />
See under MALUS – APPLE<br />
and CRABAPPLE.<br />
See General Insect and Mite<br />
Management: Caterpillars and<br />
Moths, Chapter 11.<br />
See General Insect and Mite Management: Leafhoppers, Chapter 11.<br />
See General Insect and Mite Management: Sawflies, Chapter 11.<br />
See General Insect and Mite Management: Tent Caterpillars and<br />
Skeletonizers, Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 13
Pest Description<br />
CYDONIA - QUINCE<br />
Diseases:<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Fire Blight (Erwinia amylovora): See General Disease Management: Fire Blight, Chapter 9.<br />
Rust (Gymnosporangium clavipes): This rust fungus<br />
infects quince, apple, hawthorn, cotoneaster<br />
and saskatoon. Yellow-orange pustules (aecia)<br />
appear on lower side <strong>of</strong> leaves in summer.<br />
Juniper is the alternate host. See under<br />
AMELANCHIER and MALUS.<br />
Insects:<br />
Cherry Ermine Moth: See MALUS: Apple Ermine Moth.<br />
ERICA - HEATHER (see CALLUNA)<br />
EUONYMUS<br />
Diseases:<br />
Anthracnose (Colletotrichum gloeosporioides): This<br />
warm-weather fungus (optimum 25-30 o C)<br />
causes small leaf lesions with white, grey or tan<br />
centres and dark or reddish borders. Stem<br />
cankers are small, oval and may be raised and<br />
scabby. Larger cankers may girdle the stem<br />
causing dieback. Most common on E. japonica<br />
and E. fortunei (‘Canadale Gold’ is more<br />
susceptible than ‘Emerald ’n Gold’, which is<br />
more susceptible than ‘Emerald Gaiety’).<br />
No fungicides are registered for<br />
use on quince.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply when new growth<br />
emerges and at 7-14 day<br />
intervals. Not a common disease<br />
in BC. Fungicides may be needed<br />
for control in Interior nurseries<br />
or in unusually hot weather at<br />
the Coast.<br />
Cultural Management<br />
Pick <strong>of</strong>f infected leaves. Rake<br />
up and burn, bury or<br />
compost. New infections<br />
occur each year from infected<br />
junipers. Remove nearby<br />
junipers.<br />
Collect and burn, bury or<br />
compost crop debris.<br />
Space plants for good air<br />
circulation and time watering<br />
so plants dry quickly. Plants<br />
grown under shade have a<br />
lower incidence <strong>of</strong> the disease.<br />
Prune out infected branches if<br />
possible. E. japonica does not<br />
thrive with repeated pruning.<br />
Powdery Mildew (Oidium euonymus japonica): Green cultivar ‘Patens’ is very susceptible. Variegated cultivars are not<br />
usually affected. Water forcibly sprayed on foliage under fast drying conditions may reduce disease. See General<br />
Disease Management: Powdery Mildew, Chapter 9.<br />
FORSYTHIA<br />
Diseases:<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
This bacterial disease causes dark black streaks<br />
on young shoots, <strong>of</strong>ten on one side <strong>of</strong> the shoot.<br />
Flowers wilt and turn brown. Buds are<br />
blackened. Infection occurs in cool, rainy<br />
weather in spring and fall.<br />
Stem Gall (Phomopsis sp.): This fungus causes<br />
nodular growths along stem and twigs.<br />
Multiple galls may cause reduction in vigour,<br />
or dieback <strong>of</strong> small twigs.<br />
FRAXINUS - ASH<br />
Diseases:<br />
Anthracnose (Discula sp. (Apiognomonia)): This<br />
fungus causes leaf blotches and marginal<br />
scorch in rainy springs. Premature leaf fall can<br />
occur. ‘Modesto’ ash is very susceptible and<br />
should not be grown in Coastal areas <strong>of</strong> BC.<br />
When buds start to open in<br />
spring apply:<br />
COPPER SPRAY 50: 200 g<br />
At fall leaf drop and in January<br />
apply:<br />
COPPER SPRAY 50: 600 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Begin at bud break and repeat<br />
every 7-14 days during wet<br />
weather.<br />
Improve air circulation. Prune<br />
out and destroy wilted shoots.<br />
See General Disease<br />
Management: Bacterial<br />
Blight/Canker, Chapter 9.<br />
Cut <strong>of</strong>f and destroy branches<br />
and canes that bare galls.<br />
Galls resemble those caused<br />
by crown gall bacteria, but are<br />
usually higher up in the bush.<br />
Control measures are<br />
warranted only when the<br />
disease occurs annually. Rake<br />
up and burn, bury or compost<br />
fallen leaves.<br />
14 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Leaf Spot (Cercospora sp. and other fungi): Discrete<br />
leaf spots, generally smaller than anthracnose<br />
lesions and not on margins <strong>of</strong> leaves. Severe<br />
infections may cause premature leaf fall.<br />
Rust (Puccinia sparganoides): This fungus forms aecia<br />
on leaves <strong>of</strong> ash in Central and Eastern North<br />
America only. Not known to occur in BC.<br />
Insects:<br />
Ash and Lilac Borer (Podosesia syringae): It was first<br />
reported in BC in 2006, but is well established<br />
in the US. The adult is a clearwing moth that is<br />
similar in appearance to a paper wasp. It<br />
usually has a single generation per year. The<br />
female moth deposits her eggs in bark crevices<br />
within 10 to 14 days <strong>of</strong> emergence. Upon<br />
hatching, the larvae tunnel into the trunk and<br />
feed beneath the bark. The larvae do excavate<br />
galleries in the wood. The mature, 3 cm larvae<br />
overwinter inside the tree. Adult moths emerge<br />
the following spring. Infestations lead to<br />
unsightly scars and swollen areas on the trunk<br />
and, can weaken branches. Severe infestations<br />
can kill a tree. Hosts include European ash,<br />
privet, lilac and mountain ash.<br />
Fall Webworm (Hyphantria cunea): Branches may be<br />
defoliated by hairy caterpillars with black<br />
heads and pale yellow bodies with dark stripes<br />
along back. Webs are usually on tips <strong>of</strong><br />
branches in late summer and fall. Moths are<br />
pale and 1.2 cm long.<br />
GLEDITSIA - HONEY LOCUST<br />
Insects:<br />
Honey Locust Plant Bug (Blepharidopterus chlorionis):<br />
The pest was detected in Oregon in 2008. It has<br />
one generation per year. Eggs hatch in early<br />
spring and the nymphs feed on new growth,<br />
causing stippling and leaf distortion. Adults<br />
also feed on leaves that can lead to defoliation.<br />
Honey Locust Pod Gall Midge (Dasineura gleditchiae):<br />
Pupae overwinter in the soil and adults emerge<br />
in the spring when new growth begins. The<br />
adult is a small fly (3 mm long). Eggs are laid<br />
in expanding leaflets and hatch in a few days.<br />
Larval feeding cause leaves to become globular<br />
or pod-like. The pods contain one or more<br />
whitish larvae. After 3-4 weeks <strong>of</strong> feeding, the<br />
larva pupates and an adult fly emerges. Galled<br />
leaflets may drop prematurely. Continued<br />
galling and defoliation may cause the death <strong>of</strong><br />
small branches, but new growth <strong>of</strong>ten develops<br />
at the base <strong>of</strong> dead twigs. There may be three<br />
or more generations per year.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply at spring bud break and<br />
repeat every 7-14 days as necessary.<br />
NOVA 40W: 25-34 g<br />
Apply every 10-14 days.<br />
See General Insect and Mite<br />
Management: Bark Beetles and<br />
Woods Borers, Chapter 11.<br />
Pesticide sprays should be<br />
applied before eggs hatch. Use<br />
pheromone traps (isomate-P) to<br />
monitor for moth emergence.<br />
Spray 10 to 14 days following<br />
emergence.<br />
AMBUSH 500EC: 7 mL<br />
DIPEL WP: 62.5 g<br />
DIPEL 2X DF: 31 g<br />
ORTHENE 75% SP: Mist blower<br />
= 1,312 g/1,000 L; Hydraulic<br />
sprayer = 637 g/1,000 L<br />
POUNCE 384 EC: 9 mL<br />
SEVIN T&O: 230-350 mL<br />
HORTICULTURAL OIL (97%): 1 L<br />
Use to control the eggs. Since the<br />
eggs hatch within a couple <strong>of</strong><br />
days, application timing is<br />
critical. Monitor expanding<br />
leaflets for red eggs in the spring<br />
(late March to early April) and<br />
spray when eggs are found.<br />
Cultural Management<br />
Rake up and burn, bury or<br />
compost fallen leaves.<br />
Fungicide treatment is rarely<br />
necessary.<br />
Water and mulch trees to<br />
reduce stress. Do not wound<br />
the trunk or main branches.<br />
Remove webs as soon as seen<br />
in mid-summer.<br />
See General Insect and Mite<br />
Management: Caterpillars and<br />
Moths, Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 15
Pest Description<br />
HEDERA - ENGLISH IVY<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Diseases:<br />
Bacterial Leaf Spot (Xanthomonas hortorum pv.<br />
hederae): Leaf spots are usually angular with<br />
reddish margins and exhibit dark<br />
discolouration running into the veins. Petioles<br />
and stems may become black and shriveled.<br />
Grey Mould (Botrytis cinerea): See General Disease Management: Powdery Mildew, Chapter 9.<br />
Leaf and Stem Spots/Anthracnose (Phyllosticta /<br />
Colletotrichum spp.): Circular leaf spots, <strong>of</strong>ten<br />
with concentric rings and small, black fungal<br />
fruiting bodies. Entire leaves can wilt if lesions<br />
girdle stems.<br />
HYDRANGEA<br />
Diseases:<br />
Grey Mould (Botrytis cinerea): This common fungus<br />
causes browning <strong>of</strong> petals and a grey, fuzzy<br />
mould on flower clusters during wet weather.<br />
Leaf Spots (Cercospora and Septoria spp.): Small to<br />
large leaf spots containing tiny, black fungal<br />
bodies (pycnidia). Severe infections may cause<br />
leaf drop.<br />
DITHANE DG, M-45 or WSP<br />
80WP: 125-250 g<br />
PENNCOZEB 80WP: 125-250 g<br />
Use low rate when treating s<strong>of</strong>t,<br />
new growth or when repeated<br />
applications are planned.<br />
BOTRAN 75W: 175 g<br />
ROVRAL 50WP-WDG: 100 g<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply before blooming, since<br />
may discolour blooms.<br />
Cultural Management<br />
Avoid overhead watering.<br />
Pick <strong>of</strong>f affected leaves when<br />
first spots appear.<br />
Avoid overhead watering.<br />
Remove infected plant parts if<br />
practical. Fungicides are<br />
rarely necessary in the<br />
landscape.<br />
Remove blooms after<br />
flowering. Infected flowers<br />
falling on leaves can lead to<br />
leaf and stem infections.<br />
Reduce humidity and improve<br />
air circulation.<br />
Pick <strong>of</strong>f leaves as spots<br />
appear. Collect and destroy<br />
fallen leaves. Fungicides are<br />
rarely needed for control.<br />
Powdery Mildew (Erysiphe polygoni): Lower leaf surfaces become covered with a powdery, white growth; upper surfaces<br />
may be purple-brown. Blooms may be stunted & malformed. See General Disease Management: Powdery Mildew,<br />
Chapter 9.<br />
Sunscald: When bright sunny weather follows a<br />
prolonged dull period in late spring or early<br />
summer, large areas <strong>of</strong> leaves and shoots may<br />
wilt, develop a water-soaked appearance and<br />
finally turn grey to brown.<br />
ILEX - HOLLY<br />
Diseases:<br />
Green Algae: Green to black coloured algae coating<br />
on leaves, twigs, branches and trunk.<br />
Leaf and Twig Blight (Phytophthora ilicis): Black<br />
blotches and rot <strong>of</strong> leaves and petioles,<br />
followed by leaf drop, starts on lower branches<br />
in late fall and progresses upward during cold,<br />
rainy weather in winter. Symptoms are usually<br />
observed in January. Twig cankers and berry<br />
rot may also occur.<br />
DITHANE DG, M-45 or WSP<br />
80WP: 180-250 g<br />
MANZATE DF & PRO-STICK:<br />
180-250 g<br />
PENNCOZEB 80WP: 180-250 g<br />
Apply at any time during the<br />
growing season. Do not apply<br />
close to harvest as visible residue<br />
may make holly unmarketable.<br />
DITHANE DG, M-45 or WSP<br />
80WP: 180-250 g<br />
PENNCOZEB 80WP: 180-250 g<br />
Apply in the fall before the onset<br />
<strong>of</strong> fall rains. Avoid application<br />
close to harvest to avoid visible<br />
residue.<br />
Provide temporary shade or<br />
misting during sudden hot<br />
spells that usually occur in<br />
June.<br />
Prune to increase air<br />
circulation.<br />
Prune out diseased<br />
branches and remove<br />
fallen leaves and plant<br />
debris, where practical.<br />
16 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Web Blight (Rhizoctonia solani): A white web <strong>of</strong><br />
fungal threads (mycelium) appears on leaves,<br />
blooms and stems. Affected parts may rot and<br />
drop.<br />
Insects:<br />
Bud moth (Rhopobota naevana): This moth is long (6<br />
mm) and grey to mottled-brown in colour. The<br />
larvae are dark olive-green with black heads.<br />
They produce silk that rolls the leaf for<br />
protection. Opening buds are primary targets.<br />
Eggs are laid on the underside <strong>of</strong> leaves.<br />
Overwintering eggs hatch in May. There can be<br />
two generations per year.<br />
Holly Leafminer (Phytomyza ilicis): This greyish-black<br />
fly is 12 mm long. Yellow maggots tunnel in<br />
leaves <strong>of</strong> I. aquifolium, leaving blotches that<br />
make the holly unmarketable. The eggs are laid<br />
in late May when trees are flowering.<br />
Holly Scale (Aspidiotus britannicus): Scales are light<br />
brown, oval, 12 mm across, with white, oblong<br />
egg sacks. This insect causes yellow leaf<br />
spotting and much honeydew. Black, sooty<br />
mould grows in abundant honeydew.<br />
Lecanium Scale (several species): Large, wrinkled,<br />
semi-circular scabs attach to leaves, twigs and<br />
fruit. Crawlers are present mid-July to late<br />
August. They produce much honeydew and,<br />
thus, black sooty mould.<br />
JUGLANS - WALNUT<br />
Diseases:<br />
Anthracnose (Gnomonia leptostyla; anamorph<br />
Marssonina juglandis): This fungus causes leaf<br />
spots and lesions on stems <strong>of</strong> new shoots. Stem<br />
lesions are sunken, greyish-brown with red<br />
margins. Spots also occur on husks. Nuts drop<br />
early or do not develop.<br />
Bacterial Blight (Xanthomonas arboricola pv. juglandis):<br />
Small, irregularly-shaped black spots appear<br />
on leaves and petioles. Later the spots enlarge.<br />
Black spots appear on husks and slimy decay<br />
destroys the nuts.<br />
JUNIPERUS - JUNIPER<br />
Diseases:<br />
Magnesium Deficiency: Damage is similar to that<br />
caused by Phomopsis (see Twig Blight and<br />
Dieback, below). Magnesium deficiency<br />
produces chlorotic or dead foliage in the centre<br />
<strong>of</strong> the plant, but seldom kills it.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Cultural Management<br />
Disease appears only<br />
under very wet conditions.<br />
Reduce humidity and<br />
prune or space containers<br />
to improve air circulation.<br />
Increase greenhouse<br />
ventilation.<br />
See General Insect and Mite Management: Leafminers / Needle<br />
Miners, Chapter 11.<br />
See General Insect and Mite Management: Scales, Chapter 11.<br />
Dormant:<br />
SMOTHER-OIL: 3.5 L<br />
Apply in spring before buds open. (Check label carefully as<br />
some dormant oils can be phytotoxic.)<br />
See General Insect and Mite Management: Lecanium Scale,<br />
Chapter 11.<br />
COPPER SPRAY 50: 400 g<br />
Up to 4 applications per year.<br />
KASUMIN 2L: 5 L/ha<br />
EPSOM SALTS: 1-2 kg foliar<br />
spray will give fast but shortlived<br />
results.<br />
Rake and destroy fallen<br />
leaves and nuts. Prune <strong>of</strong>f<br />
infected branches, if<br />
possible.<br />
Cut out diseased twigs<br />
and branches, if possible.<br />
On acid soils, use dolomite<br />
lime on a regular basis.<br />
Aim for a soil test with a<br />
calcium to magnesium<br />
ratio <strong>of</strong> 6-8:1.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 17
Pest Description<br />
Pear Trellis Rust (Gymnosporangium fuscum): On<br />
junipers, symptoms consist <strong>of</strong> spindle-like<br />
swellings on twigs that produce orange,<br />
gelatinous spore masses in spring. On pears,<br />
symptoms consist <strong>of</strong> orange to red blotches on<br />
the leaves. This disease is believed to be<br />
confined to the Lower Mainland and<br />
Vancouver Island south <strong>of</strong> Duncan. (See under<br />
PYRUS.) For other rusts occurring on juniper,<br />
see under AMELANCHIER and Appendix P.<br />
Root Rot (Pythium/Phytophthora spp.): Recumbent<br />
junipers are very susceptible to root rot. Foliage<br />
develops a light-green cast and gradually turns<br />
brown. Growth is poor. Bark at and below the<br />
soil line is dark brown and becomes punky.<br />
Roots are usually already decomposing by the<br />
time foliar symptoms are noticed. Foliage may<br />
be affected by twig blight pathogens (see<br />
below).<br />
Twig Blight and Dieback (Phomopsis juniperova,<br />
Kabatina juniperi, Lophodermium spp., Cercospora<br />
spp., Sclerophoma spp. and Coniothyrium spp.):<br />
Affected branch tips turn brown and<br />
progressively the entire branch may die. These<br />
fungi are <strong>of</strong>ten more damaging to winterinjured<br />
or drought-stressed plants, or plants<br />
affected by root rot or insect/rodent feeding.<br />
Insects:<br />
Cypress Tip Moth (Leafminer) (Argyresthia<br />
cupressella): Adults, small (6 mm), silvery-tan<br />
moths, are active in early June. Eggs are<br />
inserted into the green tips <strong>of</strong> one- and twoyear-old<br />
twigs. Larvae tunnel into the leaf scales<br />
and remain there until the next spring. Infested<br />
twigs become yellow then brown in late winter.<br />
A cocoon is spun around the foliage in early<br />
June <strong>of</strong> the second year for the pupal stage. Two<br />
to three weeks later, adults emerge.<br />
Juniper Scale (Carulaspis juniperi): Heavy infestations<br />
cause grey or yellowish foliage colour. Plants<br />
may die whole or in part. A black, sooty mould<br />
may grow on the honeydew secreted by the<br />
round, light-coloured scales.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DITHANE DG, M-45 or WSP<br />
80WP: 280-350 g<br />
EAGLE WSP T&O: 30 g<br />
NOVA 40W: 34 g<br />
Apply every 14 days; maximum<br />
6 applications per year.<br />
PENNCOZEB 80WP: 275-350 g<br />
Unless you are in a completely<br />
disease-free area, all nursery<br />
junipers should be sprayed at<br />
least 3 times each fall between<br />
late August and late October.<br />
COPPER SPRAY 50: 400 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
If needed, apply from April to<br />
early June to protect new growth.<br />
MALATHION 500E: 250 mL<br />
May injure Juniperus sabina.<br />
No insecticides will kill the<br />
larvae while they are inside the<br />
foliage, so timing <strong>of</strong> sprays is<br />
important. Spray infested trees<br />
when the larvae emerge to form<br />
cocoons in late April, and when<br />
eggs hatch in mid-June and again<br />
in early July.<br />
SEVIN T&O: 230-350 mL<br />
Apply in early June and repeat<br />
14 days later when crawlers are<br />
present.<br />
Cultural Management<br />
Obtain cuttings from<br />
known, certified sources.<br />
See British Columbia Plant<br />
Protection Regulations,<br />
Chapter 2, for details<br />
about shipping out <strong>of</strong> an<br />
infected area. Avoid<br />
planting ornamental pears<br />
in infected areas and do<br />
not plant junipers within<br />
30 m <strong>of</strong> pear trees.<br />
Do not plant junipers in<br />
wet, heavy or poorly<br />
drained soils in either the<br />
nursery or landscape.<br />
Avoid excessive irrigation.<br />
Root rot is common on<br />
steep banks subject to<br />
drought in summer and<br />
excessive moisture in<br />
winter. Do not allow<br />
containerized plants to<br />
stand in water. Junipers<br />
differ in their<br />
susceptibility to root rot.<br />
See General Disease<br />
Management: Root Rots<br />
Caused by Phytophthora and<br />
Pythium, Chapter 9.<br />
Select cuttings only from<br />
disease-free mother plants.<br />
Prune out dead branches<br />
or remove severely<br />
infected container plants<br />
to reduce spread <strong>of</strong><br />
infection.<br />
See General Insect and Mite<br />
Management: Scales,<br />
Chapter 11.<br />
18 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Juniper Webworm (Dichomeris marginella): Twigs and<br />
needles become webbed together, and some<br />
turn brown and die. The larva is 12 mm long,<br />
brown with reddish stripes. The adult appears<br />
in June and lays eggs that hatch about 2 weeks<br />
later. Larvae feed on the foliage during the rest<br />
<strong>of</strong> the season, overwinter and do the greatest<br />
amount <strong>of</strong> damage the following spring.<br />
Red Cedar Bark Beetle (Phloesinus sequoia): The small<br />
adult beetle lays eggs in narrow excavations in<br />
the bark. As the grubs hatch, they bore out<br />
sideways making a characteristic pattern <strong>of</strong><br />
galleries. This insect is most likely to attack<br />
newly transplanted and drought-stressed trees.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
SEVIN T&O: 230-350 mL<br />
Spray when insects first appear.<br />
Repeat in 3 weeks, if necessary.<br />
Use high pressure to ensure<br />
complete coverage.<br />
Root Weevils: See General Insect and Mite Management: Root Weevils, Chapter 11.<br />
KALMIA - MOUNTAIN LAUREL<br />
Diseases:<br />
Leaf Spot (Cercospora sp. and other fungi): Leaves<br />
exhibit irregularly-shaped to circular, lightgrey<br />
spots with a purple-brown border. Leaves<br />
may drop early.<br />
Insects:<br />
Lecanium Scale (several species): These scale insects<br />
attack a very wide range <strong>of</strong> woody plants.<br />
Large, wrinkled, semi-circular scales can be<br />
seen on leaves, stems, twigs and fruit. They<br />
produce much honeydew on which grows<br />
abundant black sooty mould.<br />
Root Weevils: Larvae chew on roots causing wilt and<br />
dieback <strong>of</strong> branches and browning <strong>of</strong> foliage.<br />
Adult weevils chew on leaves leaving<br />
unsightly notches.<br />
LIGUSTRUM - PRIVET<br />
Diseases:<br />
Leaf Spot (Cercospora and Pseudocercospora spp.):<br />
Yellow to brown leaf spots, depending on the<br />
fungal species. Spots <strong>of</strong>ten have a yellow halo.<br />
Can cause early leaf drop. Mainly in Eastern<br />
North America. Not known to occur in BC.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
See General Insect and Mite<br />
Management: Scales, Chapter 11.<br />
Cultural Management<br />
Keep trees vigorous and<br />
prevent stress.<br />
Rake and burn, bury or<br />
compost fallen leaves.<br />
Avoid overhead irrigation.<br />
These scales are <strong>of</strong>ten<br />
parasitized by beneficial<br />
organisms. If the level <strong>of</strong><br />
parasitism is high, do not<br />
apply insecticides.<br />
See General Insect and Mite Management: Root Weevils, Chapter<br />
11.<br />
DACONIL 2787F: 250 mL<br />
DACONIL 2787WDG: 140 g<br />
Apply every 7-14 days under<br />
prolonged wet conditions.<br />
Rake up and burn, bury or<br />
compost fallen leaves and<br />
plant debris.<br />
Powdery Mildew (Oidium sp.): White, powdery growth on leaves. See General Disease Management: Powdery Mildew,<br />
Chapter 9.<br />
LONICERA- HONEYSUCKLE<br />
Diseases:<br />
Honeysuckle Blight (Insolobasidium deformans<br />
(Herpobasidium deformans; Glomopsis lonicerae):<br />
Leaves develop interveinal chlorosis and<br />
necrosis, and become crinkled, cupped or<br />
twisted. Shoot blight may also occur. White<br />
fungal growth develops on the underside <strong>of</strong><br />
leaves. Worse in cool, wet, rainy, weather.<br />
DITHANE DG: 200 g<br />
MANZATE DF & PRO-STICK: 200 g<br />
Apply at green tip to ½ inch<br />
green leaf. No more than 3<br />
applications per year.<br />
Remove honeysuckle from<br />
around nurseries. Space<br />
plants for good air<br />
circulation and water early<br />
in the day. Remove plant<br />
debris before bud-break.<br />
Resistant varieties may be<br />
available.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 19
Pest Description<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Cultural Management<br />
Powdery Mildew (Microsphaera spp.): White, powdery growth on leaves. See General Disease Management: Powdery<br />
Mildew, Chapter 9.<br />
MAGNOLIA<br />
Diseases:<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
New shoots wilt and blacken. Leaves exhibit<br />
dark, irregular spots, <strong>of</strong>ten with yellow haloes.<br />
Also causes twig and branch dieback.<br />
MAHONIA - OREGON GRAPE<br />
Diseases:<br />
Leaf Spot/Anthracnose (Phyllosticta spp./<br />
Gloeosporium berberidis): The Phyllosticta fungus<br />
causes small red, circular spots that later<br />
become tan coloured in the centre. Anthracnose<br />
is characterized by larger lesions, <strong>of</strong>ten at the<br />
margins <strong>of</strong> leaves. Both diseases may occur<br />
together.<br />
Rust (Cumminsiella mirabilissima): Large spots on<br />
leaves become swollen and break open to<br />
release spores. This disease is very common at<br />
the Coast but is not serious except in unusually<br />
wet seasons.<br />
MALUS - APPLE and CRABAPPLE<br />
Diseases:<br />
Anthracnose Canker (Cryptosporiopsis curvispora):<br />
This destructive disease <strong>of</strong> apples in Coastal<br />
areas has also been found in the Kootenays and<br />
North Okanagan. Infection <strong>of</strong> new bark occurs<br />
in fall and causes small, red spots that lengthen<br />
and crack open the following spring forming<br />
“stringy” cankers. Large, girdling cankers kill<br />
entire branches. The fungus also causes a<br />
“bull’s eye” fruit rot.<br />
Fungicides applied for rust (see<br />
below) should also help to<br />
control leaf spot and<br />
anthracnose.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
SULPHUR (DOMESTIC): 0.4-0.9%<br />
liquid or other formulations. See<br />
label for rates and application.<br />
Cankers:<br />
Fungicides are generally<br />
ineffective in preventing spread<br />
<strong>of</strong> cankers. No products are<br />
specifically registered for control.<br />
Bull’s eye fruit rot:<br />
CAPTAN 50-WP: 6 kg/ha<br />
CAPTAN 80-WP: 3.75 kg/ha<br />
Apply if rainy periods occur<br />
before harvest. Do not apply<br />
within 7 days <strong>of</strong> harvest.<br />
Prune out and destroy<br />
infected shoots and<br />
branches in the dormant<br />
season and again if<br />
infection occurs in the<br />
spring. Space plants to<br />
provide good air drainage.<br />
See General Disease<br />
Management: Bacterial<br />
Blight and Canker, Chapter<br />
9.<br />
Remove and destroy<br />
infected leaves. Avoid<br />
overhead irrigation.<br />
Remove and destroy<br />
infected leaves if practical.<br />
Protect new leaves. Avoid<br />
overhead irrigation in the<br />
latter part <strong>of</strong> the day.<br />
Remove and destroy<br />
severely affected trees.<br />
Prune out and burn all<br />
cankers and infected twigs<br />
in winter or whenever<br />
they are found in the year.<br />
Isolate susceptible stock<br />
from older infected apple<br />
trees to help prevent new<br />
infections.<br />
Bull’s eye rot appears in<br />
storage although fruit is<br />
infected before harvest.<br />
Fungicides are not usually<br />
needed if good pruning<br />
and cultural practices are<br />
followed.<br />
20 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Blister Spot (Pseudomonas syringae pv. papulans):<br />
Occurs on ‘Mutsu’ and ‘Fuji’. Light spotting on<br />
‘Jonagold’. Spots on fruit start as small, green,<br />
water-soaked blisters, which later darken and<br />
expand to 4-5 mm in diameter. Leaves may<br />
exhibit a mid-vein necrosis and be curled and<br />
puckered; or have white to brown spots.<br />
Bacteria spread in water and overwinter in<br />
buds, leaf scars and fallen fruit. Fruit are<br />
susceptible to infection for about six weeks,<br />
starting about two weeks after petal fall.<br />
Crown Gall/Hairy Root (Agrobacterium tumefaciens /<br />
Agrobacterium rhizogenes): Large, warty or hairy<br />
growths appear on roots, crowns and stems.<br />
Galls on mature apples can be mistaken for<br />
physiological “burrknots” or wound callus.<br />
The bacteria spread in soil and drainage water<br />
and carry over in soil for many years. M9 and<br />
M26 rootstocks are susceptible to crown gall.<br />
Crown and Root Rot (Phytophthora cactorum): This<br />
soil-borne organism invades crowns <strong>of</strong> 3- to 10-<br />
year-old trees. Eventually, the trunk is girdled<br />
just below ground level and the tree dies. First<br />
indication <strong>of</strong> infection may be <strong>of</strong>f-colour foliage<br />
in late summer. The problem is most serious on<br />
irrigated land in the Okanagan.<br />
European Canker (Nectria galligena): Causes severe<br />
damage to apple and pear trees at the Coast.<br />
Twigs and branches wilt and die back above<br />
cankers. First-year cankers have blistered,<br />
yellowish bark. Second-year cankers develop<br />
deeply sunken edges with concentric rings.<br />
Red fungal bodies (perithecia) may be visible at<br />
the edge <strong>of</strong> cankers in fall. Most infections<br />
occur through leaf scars during fall rains but<br />
infections can occur whenever wounding and<br />
rainfall or irrigation coincide.<br />
Fire Blight (Erwinia amylovora): M9 or M26 rootstock<br />
combined with ‘Braeburn’, ‘Fuji’ or ‘Gala’ are<br />
particularly susceptible to crown infection,<br />
although it can also occur with other rootstocks.<br />
Perennial Canker (Cryptosporiopsis perennans): Fungal<br />
cankers consist <strong>of</strong> overlapping concentric rings<br />
<strong>of</strong> woody tissue. Each year the canker enlarges,<br />
gradually girdling the limb or trunk. This<br />
disease is common in the Okanagan but rare in<br />
Coastal areas. Causes “bull’s-eye” rot on fruit.<br />
Very similar to anthracnose.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
ALIETTE WDG: 2.5 kg/ha<br />
Start at petal fall and repeat at 7<br />
day intervals. Maximum 3<br />
applications per year; no more<br />
than 10 kg/ha before harvest.<br />
BORDEAUX MIXTURE: 100 g<br />
COPPER 53W + 600 g<br />
HYDRATED LIME<br />
Start applying 10 days after calyx<br />
and repeat at 10 day intervals.<br />
Do not apply either product<br />
within 30 days <strong>of</strong> harvest.<br />
No effective chemical control.<br />
DYGALL (A. radiobacter) root dip<br />
is not registered for use on<br />
apples because it has been shown<br />
to be generally ineffective in<br />
preventing infection <strong>of</strong> this crop.<br />
Orchards - foliar or drench:<br />
ALIETTE WDG: Rate varies with<br />
tree density. Read label carefully.<br />
Drench:<br />
RIDOMIL GOLD: 1 mL/5 L <strong>of</strong><br />
water/tree<br />
In Coastal areas, BORDEAUX<br />
MIXTURE as for fire blight,<br />
applied twice at leaf fall, may<br />
help reduce spread <strong>of</strong> cankers.<br />
Cultural Management<br />
The disease is worse in<br />
years when very wet<br />
weather occurs while<br />
green fruit are sizing.<br />
Follow good pruning and<br />
tree care practices;<br />
disinfect pruners between<br />
cuts. Remove fallen<br />
(windfall) fruit and bury<br />
or compost.<br />
See General Disease<br />
Management: Crown Gall,<br />
Chapter 9.<br />
Nursery stock should be<br />
planted in disease-free soil.<br />
For propagation, avoid<br />
soils and irrigation water<br />
with a history <strong>of</strong> crown rot.<br />
M4, M9 and and M26, and<br />
M2 to a lesser extent, are<br />
more resistant than other<br />
commonly-used rootstocks.<br />
The disease is worse in<br />
very wet years. Prune out<br />
infected branches below<br />
cankers and burn or bury.<br />
The fungus can continue<br />
to produce spores on dead<br />
wood.<br />
Nurseries: Destroy<br />
infected trees. Old infected<br />
apple and pear trees near<br />
the nursery should also be<br />
destroyed.<br />
See General Disease Management: Fire Blight, Chapter 9.<br />
Bull’s eye fruit rot:<br />
CAPTAN 50-WP: 6 kg/ha<br />
CAPTAN 80-WP: 3.75 kg/ha<br />
MAESTRO 80DF: 3.75 kg/ha<br />
Cankers:<br />
Research suggests fungicides are<br />
generally ineffective in<br />
preventing spread <strong>of</strong> cankers. No<br />
fungicides are specifically<br />
registered.<br />
Control the woolly apple<br />
aphid that can spread the<br />
disease. Prune out cankers<br />
whenever possible.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 21
Pest Description<br />
Powdery Mildew (Podosphaera leucotricha): The<br />
fungus overwinters in terminal buds. Greyishwhite<br />
fungus appears in felt-like patches on<br />
leaves, twigs, blossoms and fruit. Leaves<br />
become curled and distorted.<br />
Rust (Quince Rust, Gymnosporangium clavipes): Causes<br />
yellow to brown spots on upper surface <strong>of</strong><br />
leaves. Fungal fruiting bodies (aecia) form on<br />
lower surface in summer. Alternate hosts are<br />
junipers. Cedar-apple rust infects trees in<br />
eastern North America, but is not known to<br />
occur in BC.<br />
Usually a minor disease west <strong>of</strong> the Rockies,<br />
not requiring control. Remove junipers from<br />
the vicinity.<br />
Scab (Venturia inaequalis): This disease causes<br />
shedding <strong>of</strong> blossoms and scab on leaves and<br />
fruit. Scabs begin as water-soaked spots that<br />
become velvety-green, then brown and dead.<br />
Diseased leaves can be curled and distorted.<br />
New infections may occur whenever there is a<br />
moderate to prolonged rainy period.<br />
Viruses:<br />
Several viruses occur in apples, some causing little<br />
noticeable effect unless combined during<br />
budding or grafting. Virus-free propagating<br />
material is more vigorous than infected stock<br />
and gives a much better success rate.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Cultural Management<br />
unit area if indicated)<br />
See General Disease Management: Powdery Mildew, Chapter 9.<br />
For a list <strong>of</strong> resistant crabapple varieties, see Appendix D.<br />
FERBAM 76 WDG: see label for rates. May cause fruit<br />
russeting on ‘Golden Delicious’, ‘Jonathan’ and some other<br />
varieties (see label).<br />
DITHANE DG, M-45 or WSP 80WP: 150-200 g<br />
INSPIRE: 292 mL/ha<br />
MANZATE DF & PRO-STICK: 5-6 kg/ha<br />
PENNCOZEB 75DF & 80WP: 150-200 g<br />
POLYRAM DF: 4.5-6 kg/ha<br />
Flowering crabapple:<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
NOVA 40W: 34 g<br />
Apply every 10-14 days. No more than 6 applications per year.<br />
Protect new growth starting at<br />
pink-bud stage. Apply fungicide<br />
at least twice, 10 days apart. Use<br />
the higher rate for early sprays<br />
and the lower rate for later cover<br />
sprays or when disease pressure<br />
is low.<br />
Rake and burn, bury or<br />
compost fallen leaves, if<br />
practical. Grow scab<br />
resistant varieties. For<br />
resistant crabapples see<br />
Appendix D.<br />
Refer to the Ministry’s Tree Fruit Production Guide for<br />
additional chemical control options.<br />
BANNER MAXX: 14 mL<br />
COMPASS 50WG: 14-17.5 g<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
DITHANE DG, M-45 or WSP 80WP: 150-200 g<br />
EQUAL 65 WP: 1.08-2.25 kg/ha<br />
FLINT 50WG: 140-175g/ha<br />
INSPIRE: 292 mL/ha<br />
KUMULUS DF: 400-750 g<br />
NOVA 40W: 34 g<br />
PENNCOZEB 75DF & 80WP: 150-200 g<br />
POLYRAM DF: 4.5-6 kg/ha<br />
PRISTINE WG: 1.0 kg/ha<br />
SULPHUR (DOMESTIC and COMMERCIAL): See labels. May<br />
cause fruit russeting at high temperature.<br />
Use virus-free rootstocks<br />
and budwood.<br />
22 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Insects and Mites:<br />
Apple Ermine Moth (Yponomeuta malinella): The moth has a 10-12<br />
mm wing span, is white with many black spots on the wings<br />
and appears from June to August. Each female lays 10 or<br />
more eggs in one batch and covers them with a substance that<br />
dries into a hard flat scale about three to four mm in diameter<br />
and the colour <strong>of</strong> the bark. When eggs hatch the young larvae<br />
remain under the scale (called a hibernaculum) until the<br />
following spring. When the larvae emerge, they make a small<br />
tent and feed on leaves <strong>of</strong> apple and hawthorn.<br />
Apple Maggot (Rhagoletis pomonella): The larval stage<br />
damages apples and other fruit by tunnelling<br />
through them. The principal hosts are apple,<br />
crabapple and hawthorn trees, however it also<br />
occasionally attacks plum, cherry, peach and<br />
pear trees. The maggot was found for the first<br />
time in BC in 2006.<br />
Apple and Thorn Skeletonizer (Eutromula pariana):<br />
Monitor for caterpillars 2-3 weeks after leaves<br />
open.<br />
Codling Moth (Cydia pomonella): The pinkish-white<br />
larvae overwinter in cocoons under loose bark,<br />
in the soil or in trash at the base <strong>of</strong> trees. Larvae<br />
pupate in spring and adults emerge in May<br />
and June. Female moths lay eggs on fruit or on<br />
leaves near fruit. Soon after emerging, the<br />
larvae bore deep into the fruit. Up to 3<br />
generations in a year.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
CYMBUSH 250EC: 400 mL/ha<br />
DIAZINON 50WSP: 100 g<br />
DIAZINON 50EC: 100 mL<br />
IMIDAN 50-WP: 3.75 kg/ha<br />
RIPCORD 400 EC: 7.5 mL<br />
SURROUND WP: 25-50 kg/ha<br />
Cultural Management<br />
See General Insect and Mite<br />
Management: Caterpillars<br />
and Moths, Chapter 11.<br />
Malus stock must be<br />
certified free from this pest<br />
to be shipped out <strong>of</strong> BC.<br />
See Federal Plant<br />
Quarantine Regulations:<br />
Comment 7, Chapter 2.<br />
Apple maggot is a<br />
quarantine pest in Canada,<br />
and regulatory controls<br />
are in place to prevent<br />
spread from the Lower<br />
Mainland and Vancouver<br />
Island. See Federal Plant<br />
Quarantine Regulations:<br />
Comment 6, Chapter 2.<br />
See General Insect and Mite Management: Caterpillars and Moths,<br />
Chapter 11.<br />
AMBUSH 500 EC: 400 mL/ha<br />
DIAZINON 50EC: 100 mL<br />
DIAZINON 50WSP: 100 g<br />
CONFIRM 240F (crabapple): 33-60 mL<br />
CYMBUSH 250EC: 400 mL/ha<br />
DECIS 5EC: 6.8-8.5 mL<br />
IMIDAN 50-WP: 3.75 kg/ha<br />
MALATHION 500E: 250 mL<br />
POUNCE 384 EC: 17.5 mL<br />
RIPCORD 400 EC: 7.5 mL<br />
Apply bands <strong>of</strong> corrugated<br />
cardboard to the trunk and<br />
scaffold limbs in early<br />
August to collect mature<br />
larvae exiting the fruit.<br />
Remove and burn the<br />
bands after harvest. Pick<br />
and crush infested fruit.<br />
Forest Tent Caterpillar (Malacosoma disstria): See General Insect and Mite Management: Caterpillars and Moths, Chapter 11.<br />
Leafrollers (several species): These insects are leaf<br />
and fruit feeders. Deep holes that scab over are<br />
produced on the fruit. The larvae are green<br />
with black heads. They drop on a silk thread<br />
when disturbed.<br />
AMBUSH 500 EC: 400 mL/ha<br />
DIAZINON 50EC or 50WSP: 100 mL or 100 g<br />
CYMBUSH 250EC: 400 mL/ha<br />
DECIS 5 EC: 6.8 mL<br />
DIPEL WP: 2.25-3.35 kg/ha<br />
DIPEL 2X DF: 1.125-1.675 kg/ha<br />
DOKTOR DOOM: 60-480 mL/0.4 ha<br />
FORAY 48BA: 2.8-4.0 L/ha<br />
IMIDAN 50-WP: 3.75 kg/ha<br />
MALATHION 500E: 180-250 mL<br />
POUNCE 384 EC: 17.5 mL<br />
RIPCORD 400 EC: 7.5 mL<br />
SEVIN T&O: 230-350 mL<br />
SURROUND WP: 25-50 kg/ha<br />
Dormant only:<br />
SUPERIOR 70 OIL: 2 L<br />
Oyster Shell Scale: See General Insect and Mite Management: Scales, Chapter 11.<br />
Pearleaf Blister Mite (Phytoptus pyri): Green blisters<br />
occur on leaves, later turning brown and<br />
drying up. Mites also attack developing fruit<br />
causing russeting and deformity.<br />
DIAZINON 50WSP: 150 g + 1 L<br />
<strong>of</strong> Horticultural Oil<br />
True dormant stage only:<br />
LIME SULPHUR 23%: 10 L<br />
See General Insect and Mite<br />
Management: Mites,<br />
Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 23
Pest Description<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Cultural Management<br />
unit area if indicated)<br />
San Jose Scale: Only occurs in the South Okanagan but can be very damaging when present. See General Insect and<br />
Mite Management: Scales, Chapter 11.<br />
Woolly Apple Aphid (Eriosoma lanigerum): Aphid DIAZINON 50EC: 50-100 mL<br />
feeding results in nodular swellings or galls. DIAZINON 50WSP: 50-100 g<br />
The perennial canker fungus can infect injured DECIS 5 EC: 6.8 mL<br />
tissue (see above). The aphid can be detected INSECTICIDAL SOAP 25%: 5 L<br />
by the cottony white masses it forms around IMIDAN 50-WP: 3.75 kg/ha<br />
pruning cuts, water sprouts and leaf axils. POUNCE 384 EC: 9 mL<br />
PHOTINIA<br />
Diseases:<br />
Leaf Spot (Fabrea Blight) (Diplocarpon mespili<br />
(Entomosporium mespili)): Small, dark, reddish<br />
spots appear and coalesce to form blotches on<br />
the leaf surface. Defoliation can occur if<br />
infection is severe.<br />
PICEA - SPRUCE<br />
Diseases:<br />
Botrytis Blight (Botrytis cinerea): Affects spruce, fir,<br />
hemlock and cedar. Causes seedling blight in<br />
greenhouses and container nurseries. Under<br />
cool, moist conditions branches die and become<br />
covered with a web <strong>of</strong> grey fungal mycelium.<br />
Botryosphaeria Canker and Dieback (Botryosphaeria<br />
sp.): Botryosphaeria causes disease on stressed<br />
plants. It overwinters on plant debris and on<br />
healthy bark and leaves. It enters plants<br />
through wounds or natural openings. Infection<br />
leads to the development <strong>of</strong> cankers that result<br />
in wilting and branch dieback.<br />
Cytospora Canker (Cytospora kunzei): Rain-splashed<br />
spores infect through wounds and develop<br />
cankers at the base <strong>of</strong> the trunk or twigs.<br />
Branches near the ground may die. Cankers are<br />
<strong>of</strong>ten not visible on the bark; you must cut into<br />
the bark to expose the diseased tissue. Fruiting<br />
bodies <strong>of</strong> the fungus (small black dots) may be<br />
seen on the canker.<br />
Needle Cast (Rhizosphaera kalkh<strong>of</strong>fi): Small yellow to<br />
greyish-green mottled spots, which later turn<br />
purplish-brown, appear on current year needles<br />
<strong>of</strong> lower branches. Infected needles turn colour<br />
and fall about one year after infection. Long<br />
periods <strong>of</strong> wet foliage and warm temperatures<br />
promote the disease. P. pungens (blue spruce) is<br />
particularly susceptible.<br />
Rust (Chrysomyxa spp.): Rust pustules appear as<br />
white blisters on the lower surface <strong>of</strong> needles.<br />
Affected needles turn yellow and may drop<br />
prematurely. Spruce cone rusts can also be a<br />
problem in seed orchards.<br />
Greenhouse only:<br />
IMPOWER 60WP: see label for rate and application.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Application <strong>of</strong> fungicide at bud<br />
break and again one week later<br />
will provide some control.<br />
Rake up and burn, bury or<br />
compost fallen leaves.<br />
Avoid overhead watering.<br />
See General Disease Management: Botrytis Blight / Canker, Chapter 9.<br />
Ensure plants are healthy<br />
and, avoid plant stress<br />
and injury. Follow<br />
appropriate sanitation<br />
practices (e.g. prune out<br />
dead wood, collect and<br />
dispose <strong>of</strong> leaf debris).<br />
Control weed growth and<br />
remove lower branches to<br />
improve air circulation at<br />
the base <strong>of</strong> the tree.<br />
BANNER MAXX: 35 mL (for use on Christmas trees only)<br />
BRAVO Ultrex 90 SDG: 5.2 kg/ha<br />
COPPER SPRAY 50: 400 g; apply under fast drying conditions<br />
to avoid needle damage.<br />
DACONIL 2787F: 9.5 L/ha<br />
DACONIL Ultrex: 5.75 kg/ha<br />
FLINT 50WG: 210g/ha<br />
Avoid shearing infected trees when the foliage is wet.<br />
See General Disease Management:<br />
Rusts, Chapter 9.<br />
Rusts are not common on<br />
spruce, but can <strong>of</strong>ten be<br />
controlled by removing<br />
the alternate host from the<br />
area (usually a native<br />
broad-leaved shrub).<br />
24 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Sydowia Blight/Tip Blight (Sclerophoma spp.): Usually<br />
a secondary fungus growing on needles<br />
damaged by other factors, but can cause<br />
dieback <strong>of</strong> new shoot tips on P. pungens. Black<br />
fungal bodies are abundant on new needles.<br />
Shoot tips become distorted and brown.<br />
Seedling Blight (Sirococcus conigenus): Death <strong>of</strong><br />
young shoots (tipblight) on spruce and<br />
hemlock. Shoots <strong>of</strong>ten curl to form a “hook”.<br />
Causes seed decay and seedling blight on pine,<br />
spruce, hemlock, fir and occasionally Douglas<br />
fir. Dead seedlings remain upright and needles<br />
die from the bases upward. Black fungal bodies<br />
(pycnidia) sporulate on dead tissue and cone<br />
scales. The fungus is seed-borne.<br />
Insects and Mites:<br />
Cooley Spruce Gall Adelgid (Adelges cooleyi): The<br />
insect attacks both spruce and Douglas fir. The<br />
adult female overwinters on bark near terminal<br />
buds and lays eggs in the spring. The crawlers<br />
that emerge from the eggs move to the base <strong>of</strong><br />
needles on the new shoot and begin to feed.<br />
Adelgid feeding causes shoot tips to develop<br />
into cone-like galls (1.2-5.0 cm long). In the<br />
summer, the cones turn brown and open,<br />
releasing adelgids.<br />
Hemlock Woolly Adelgid (Adelges tsugae): This<br />
sucking insect appears as white, cottony puffs<br />
on the bark and base <strong>of</strong> needles. Infestation<br />
<strong>of</strong>ten leads to the production <strong>of</strong> abundant<br />
black, sooty mould. Premature needle drop<br />
may occur.<br />
See Comment 30 in Federal Plant Quarantine<br />
Regulations in Chapter 2.<br />
Sitka Spruce Weevil (Pissodes stobi): Adult weevils<br />
are reddish-brown and 5-7 mm long. Larvae<br />
are legless, creamy white with brown heads<br />
and up to 7 mm long. In the spring, adults lay<br />
eggs in the bark <strong>of</strong> the leader. Larvae feed<br />
under the bark causing the new terminal to<br />
wilt, droop and die. Young trees can be killed.<br />
Spruce Aphid (Elatobium abietinum): This small, dull<br />
green, sucking insect causes older needles to<br />
turn brown and drop. The tree may be killed if<br />
attacked two to three years in a row.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER SPRAY 50: 400 g<br />
Apply when new growth starts<br />
in spring and repeat at 10-day<br />
intervals. May cause needle<br />
spotting if applied under cool,<br />
cloudy conditions.<br />
BRAVO Ultrex 90 SDG: 2-3.3<br />
kg/ha<br />
DACONIL 2787F: 3.6-6.0 L/ha<br />
DACONIL Ultrex: 2.9-3.6 kg/ha<br />
See application instructions<br />
above for Needle Cast.<br />
ACECAP 97: Apply when<br />
wingless, crawler forms are first<br />
seen in spring. For rate, see label<br />
or General Insect and Mite<br />
Management: Aphids, Chapter 11.<br />
INSECTICIDAL SOAP 47% or<br />
50.5%: 2 L<br />
THIONEX EC : 125-175 mL<br />
THIONEX 50 W: 100 g<br />
INSECTICIDAL SOAP 47% or<br />
50.5%: 2 L; spray after May 1<br />
LANDSCAPE OIL: 1-2 L to<br />
control eggs, nymphs and adults<br />
on Picea jezoensis and P. polita<br />
See General Insect and Mite<br />
Management: Woolly Adelgids,<br />
Chapter 11.<br />
CYGON 480-ORN or LAGON<br />
480 E: 2.5 L<br />
Thoroughly spray terminal to<br />
run-<strong>of</strong>f at time <strong>of</strong> egg laying.<br />
DURSBAN WSP: 33.6 g<br />
PRO DURSBAN TURF: 37.5 mL<br />
INSECTICIDAL SOAP 47% or<br />
50.5%: 2 L<br />
PYRATE 480EC: 37.5 mL<br />
Apply as soon as aphids appear<br />
in February.<br />
Greenhouse only:<br />
IMPOWER 60WP: See label.<br />
Cultural Management<br />
Infection <strong>of</strong>ten follows<br />
winter damage to young<br />
growing shoots.<br />
See General Disease<br />
Management: Sirococcus<br />
Blight, Chapter 9 for more<br />
information on controlling<br />
seed and seedling disease.<br />
Monitor from late October<br />
to April if there has been a<br />
problem with galls in<br />
previous years. Remove<br />
and destroy green galls as<br />
soon as they appear.<br />
Nitrogen fertilization has<br />
been shown to enhance<br />
adelgid survival and<br />
negate pest control<br />
measures. If this insect is a<br />
problem, reduce nitrogen<br />
fertilization as much as<br />
possible.<br />
Clip and destroy wilted<br />
leaders as they appear.<br />
If not controlled, needles<br />
may drop in May-June.<br />
Early treatment is<br />
essential.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 25
Pest Description<br />
Spruce Budworm (Choristoneura fumiferana) and<br />
Other Caterpillars: This budworm affects<br />
spruce, balsam fir, Douglas fir, pine, hemlock<br />
and larch. The caterpillar, which is dark<br />
reddish-brown with yellow stripes, chews on<br />
opening buds and needles.<br />
Spruce Spider Mite (Oligonychus ununguis): Needles<br />
become yellow and covered with a silky<br />
webbing. Mites are pale green when young and<br />
darken with age. They overwinter as eggs on<br />
twigs and needles. This mite also attacks<br />
Juniperus, Thuja and Tsuga.<br />
PIERIS - ANDROMEDA<br />
Diseases:<br />
Dieback and Root Rot (Phytophthora spp.): This<br />
organism infects roots and causes root decay.<br />
Plants eventually die. Leaves may also be<br />
infected.<br />
Phomopsis Blight (Phomopsis amygdali): Phomopsis<br />
blight is a new disease that causes stem cankers,<br />
shoot dieback and blight symptoms on Pieris.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Cultural Management<br />
unit area if indicated)<br />
See General Insect and Mite Management: Spruce Budworm,<br />
Chapter 11.<br />
VENDEX 50W: 50-100 g<br />
Apply in June or August as<br />
necessary.<br />
Dormant spray:<br />
SUPERIOR 70 OIL: 2 L<br />
Greenhouse only:<br />
AVID 1.9% EC: 30 mL<br />
Insects:<br />
Andromeda Lace Bug (Stephanitis takeyai): See Lace Bugs, Chapter 11.<br />
PINUS - PINE<br />
Diseases:<br />
Needle Cast (Lophodermium seditiosum): In BC, only<br />
the short-needled varieties <strong>of</strong> Scots pine are<br />
normally damaged. Most infections occur in<br />
late summer on new needles. Distinct spots<br />
appear on needles during the winter and<br />
following summer. Large, black, elliptical,<br />
fungal bodies appear in needle spots. Infected<br />
needles then turn yellow and brown and drop.<br />
Severely affected trees normally have at least<br />
one season’s needles attached at any time. On<br />
occasion, however, even these needles yellow<br />
and fall leaving the tree almost bare.<br />
Foliar dieback:<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
Apply at new leaf emergence.<br />
Root rot: See General Disease<br />
Management: Root Rots Caused by<br />
Phytophthora and Pythium,<br />
Chapter 9.<br />
At the end <strong>of</strong> July, end <strong>of</strong><br />
August and the end <strong>of</strong><br />
September apply:<br />
BRAVO Ultrex 90 SDG: 1.3-2.7 kg/ha<br />
COPPER SPRAY 50: 400 g<br />
May cause needle spotting; apply<br />
in fast-drying conditions.<br />
DACONIL 2787F: 2.4-4.8 L/ha<br />
DACONIL Ultrex: 1.45-2.9 kg/ha<br />
DITHANE DG, M-45 or WSP<br />
80WP: 250 g<br />
PENNCOZEB 80WP: 250 g<br />
In dense plantings, and those<br />
with a history <strong>of</strong> needle cast,<br />
begin 2 weeks earlier and<br />
continue applications into<br />
October.<br />
See General Insect and Mite<br />
Management: Mites,<br />
Chapter 11.<br />
Practice good sanitation in<br />
propagation. Avoid heavy,<br />
wet soils and areas where<br />
other species have died<br />
out as a result <strong>of</strong><br />
Phytophthora infection.<br />
Container plants should<br />
have good drainage within<br />
and below the pot.<br />
Space plants for good air<br />
circulation. Pines normally<br />
shed old needles and<br />
needle-shed can be more<br />
severe after dry summers.<br />
Other Lophodermium spp.<br />
(which produce similar<br />
black, elliptical fungal<br />
bodies on needles), and<br />
other fungi <strong>of</strong>ten invade<br />
dead and dying needles,<br />
but do not cause disease.<br />
26 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Needle Cast (Cyclaneusma minus): Premature cast <strong>of</strong> 2<br />
and 3-year old needles. Brown bands on<br />
yellowing needles appear in late summer/fall.<br />
White fungal fruiting bodies develop within<br />
the bands about one month later. These release<br />
spores in winter and early spring which cause<br />
new infections, although needles will not show<br />
symptoms until fall.<br />
Needle Cast (Lophodermella spp.): Needles turn<br />
reddish-brown in spring then straw-coloured.<br />
Fungal fruiting bodies, usually black but<br />
sometimes colourless, appear on the infected<br />
needles. Spores cause new infections from bud<br />
break until new growth ceases, in periods <strong>of</strong><br />
wet weather.<br />
Needle Cast (Elytroderma deformans): Affects only 2-<br />
and 3-needled pines, mainly ornamentals.<br />
Needles turn reddish-brown in spring fading to<br />
tan or grey in fall before dropping. Black,<br />
elongated, fungal fruiting bodies develop on<br />
infected needles in summer and release spores<br />
in the fall, or the next spring, causing new<br />
infections. Twig infections produce a “witches’<br />
broom”.<br />
(Scirrhia) Needle Blight (Mycosphaerella pini<br />
(Dothistroma septospora)): Yellow spots on<br />
needles enlarge to form a red band. Needles<br />
die back from the tips above the band. Disease<br />
usually spreads from the base <strong>of</strong> the tree<br />
upward. Black, fungal fruiting bodies appear<br />
on needles, which are cast prematurely.<br />
Scleroderris Canker (Gremmeniella abietina): Does not<br />
occur in BC. Causes shoot blight and cankers<br />
on pines and Balsam fir in Eastern N. America.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Fungicide applications are <strong>of</strong>ten<br />
ineffective, since spores can<br />
infect needles whenever the<br />
temperature is above freezing.<br />
Fungicides applied for<br />
Lophodermium needle cast (above)<br />
should also control Lophodermella.<br />
Apply fungicides at bud break<br />
and again about one month later.<br />
Fungicides have been shown to<br />
be generally ineffective for<br />
control <strong>of</strong> this disease. None are<br />
specifically registered.<br />
BRAVO Ultrex 90 SDG: 5.2<br />
kg/ha<br />
COPPER SPRAY 50: 400 g<br />
May cause needle spotting; apply<br />
under fast drying conditions.<br />
DACONIL 2787F: 9.5 L/ha<br />
DACONIL Ultrex: 5.75 kg/ha<br />
DACONIL 2787F: 2.4-4.8 L/ha<br />
BRAVO Ultrex 90 SDG: 1.3-2.7 kg/ha<br />
DACONIL Ultrex: 1.45-2.9 kg/ha<br />
Cultural Management<br />
Reduce water and<br />
nutritional stress, control<br />
weeds and space trees for<br />
good air circulation.<br />
Control weeds and space<br />
trees for good air<br />
circulation.<br />
Landscape Trees:<br />
Remove infected needles<br />
and rake up and destroy<br />
fallen ones.<br />
Prune out and destroy<br />
“witches’ brooms”. Rake<br />
up and burn, bury or<br />
compost old needles.<br />
Replace severely infected<br />
trees with resistant<br />
species.<br />
Do not plant near diseased<br />
trees. Remove lowest<br />
branches. Control weeds<br />
and space trees for good<br />
air circulation.<br />
Landscape trees: Remove<br />
infected needles, rake up<br />
fallen needles and burn,<br />
bury or compost.<br />
See Federal Plant<br />
Quarantine Regulations:<br />
Comment 14, Chapter 2.<br />
Seedling Blight (Sirococcus conigenus): See under PICEA and General Disease Management: Sirococcus Blight, Chapter 9.<br />
Western Gall Rust (Endocronartium harknessii): No See General Disease Management: Western Gall Rust, Chapter 9.<br />
alternate host is required for this rust fungus.<br />
Rough, globular galls appear on branches or<br />
trunk several years after the infection occurred.<br />
Fungus is orange when fruiting. Infects hard<br />
pines (2- and 3-needled pines) such as lodgepole,<br />
mugho, Austrian, Scots and ponderosa.<br />
White Pine Blister Rust (Cronartium ribicola): This Chemical control is considered to be impractical on pines.<br />
rust attacks only 5-needled pines. Alternate<br />
hosts are currants and gooseberries. The rust Management: Do not grow 5-needled pines in Coastal BC, the<br />
attacks the living bark and cambium <strong>of</strong> white West Kootenays, or Northern Vancouver Island. Do not grow<br />
pine. First year symptoms <strong>of</strong> infection are currants or gooseberries in Interior BC where Ribes are<br />
blisters with secretions <strong>of</strong> pitch. In subsequent common. See General Disease Management: Rusts, Chapter 9.<br />
years, bright orange fungal spores appear in<br />
May on the rust cankers. Cankers eventually<br />
kill the infected branches.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 27
Pest Description<br />
Insects:<br />
European Pine Shoot Moth (Rhyacionia buoliana):<br />
Insect presence is indicated from September to<br />
June by excess resin at buds and wilting shoots.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Cultural Management<br />
See General Insect and Mite Management: European Pine Shoot<br />
Moth, Chapter 11.<br />
Pine Bark Aphid (Pineus strobi): This aphid feeds on the trunk and is recognized by a white cottony material in<br />
patches on the trunk. Several generations are produced during summer. See General Insects and Mite<br />
Management: Aphids and Adelgids, Chapter 11.<br />
Pine Needle Scale (Chionaspis pinifoliae): The scale is<br />
2.5 mm long, white with a yellow spot at one<br />
end. Needles may appear nearly white when<br />
heavily infested.<br />
Spray the crawler stage with one <strong>of</strong> the following<br />
insecticides in late May to early June:<br />
MALATHION 85E: 244.5 mL<br />
ORTHENE 75% SP: Mist blower = 1,312 g/1,000 L; Hydraulic<br />
sprayer = 637 g/1,000 L<br />
SEVIN T&O: 230-350 mL<br />
Dormant spray:<br />
SUPERIOR 70 OIL: 2 L<br />
Pine Sawflies (Neodiprion spp.): There are at least 4 CYGON 480-ORN, or LAGON 480E: 100 mL<br />
different species <strong>of</strong> sawflies that damage pines DURSBAN WSP: 44.8 g<br />
in BC. The larvae, which range in length from PRO DURSBAN TURF: 50 mL<br />
21-25 mm long, are voracious defoliators that SEVIN T&O: 230-350 mL<br />
can totally consume 1-year and older foliage. TRISTAR 70 WSP: 1 pack/1,000 L<br />
This gives the tree a bottle-brush appearance as<br />
the new growth develops. They overwinter as See General Insects and Mite Management: Sawflies, Chapter 11.<br />
eggs; larvae emerge in the spring. Mature larvae<br />
drop to the ground in mid-June to pupate. The<br />
emerging female adults lay eggs in slits along<br />
the margins <strong>of</strong> current season needles.<br />
Sequoia Pitch Moth (Synanthedon sequoiae) and<br />
Northern Pitch Twig Moth (Petrova<br />
albicapitana): Pitch moths damage both<br />
ornamental and native pines in BC. The<br />
sequoia pitch moth may attack any suitable<br />
host tree over 2 m in height, whereas the<br />
northern pitch twig moth is primarily a pest <strong>of</strong><br />
saplings (= 0.3 to 3.0 m in height). The larvae <strong>of</strong><br />
both species burrow into the main stem or<br />
branches. Damage is easily located by the large<br />
pitch masses produced at the entry points.<br />
Larval feeding can kill terminal shoots or<br />
produce weakened and crooked trunks.<br />
PLATANUS - SYCAMORE, PLANE TREE<br />
Diseases:<br />
Anthracnose (Apiognomonia veneta): This fungal<br />
disease overwinters in cankers on infected<br />
twigs and dead leaves. In early spring, young<br />
leaves are killed as they emerge from buds.<br />
Later infection causes brown blotches on either<br />
side <strong>of</strong> the mid-vein, and severe defoliation<br />
may result. Twigs and branches can be girdled<br />
and killed. It is most severe in warm, wet<br />
springs.<br />
There are no effective pesticide controls for pitch moths.<br />
Management Options:<br />
Protect trees from injury; pitch moths more frequently attack<br />
pines that have pruning wounds or other injuries than<br />
uninjured pines.<br />
Remove infested branches. Prune in the fall so the wounds<br />
begin to close before the egg-laying adults emerge in spring.<br />
Physically remove pitch masses and kill the enclosed larva or<br />
pupa. There will be a single larva/pupa per mass. Physical<br />
removal can reduce re-infestations and local populations. The<br />
insect will have emerged from masses that are 2 or more years<br />
old. Older masses are harder and darker in colour.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex:150 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Apply at bud break and repeat<br />
every 7–14 days during wet<br />
weather in the early part <strong>of</strong> the<br />
growing season.<br />
Rake fallen leaves and burn,<br />
bury or compost. Prune out<br />
diseased branches.<br />
Fungicide treatments are not<br />
necessary or beneficial on<br />
large landscape trees: see the<br />
Ministry’s Home and Garden<br />
Guide. Some varieties <strong>of</strong><br />
Platanus including the<br />
London Plane are generally<br />
less susceptible.<br />
28 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Sooty Mould: Black mould appears on leaves. It<br />
grows on honeydew produced by aphids,<br />
whiteflies, scales, mealy bugs and leafhoppers.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
POPULUS - POPLAR AND ASPEN (COTTONWOOD)<br />
Diseases:<br />
Leaf Blister (Taphrina spp.): Bright, yellow-brown<br />
blisters <strong>of</strong> various sizes occur on leaves after<br />
long periods <strong>of</strong> cool, wet weather.<br />
Leaf Spot (Marssonina populi, Septoria populicola and<br />
other spp.): Brown spots or blotches appear on<br />
leaves and small cankers form on green twigs.<br />
Early defoliation and reduced growth may<br />
occur especially during wet years when<br />
symptoms are severe.<br />
Rust (Melampsora spp.): Yellow, then brown leaf spots<br />
occur in late summer/fall. Leaves may drop<br />
early. Spores released from yellow pustules on<br />
leaves cause the disease to spread. Older<br />
pustules turn brown. Alternate hosts are Abies,<br />
Larix, Picea, Pinus, Pseudotsuga and Tsuga.<br />
Needles are infected in spring by spores from<br />
fallen poplar leaves.<br />
Shoot Blight (Venturia tremulae): Dark brown to black<br />
lesions form on succulent leaves and new<br />
shoots. Leaves wither and dying shoots form a<br />
“shepherd’s crook” at the tip.<br />
Insects:<br />
Poplar and Willow Borer (Cryptorhynchus lapathi):<br />
Larvae (grubs) attack limbs and trunks causing<br />
black, swollen scars. Old damage is indicated<br />
by death <strong>of</strong> small stems, 2-8 cm in diameter.<br />
Current damage is indicated by splits and holes<br />
in bark from which sap and sawdust exude.<br />
Affected limbs may break <strong>of</strong>f. The adult weevil<br />
is greyish-brown with a wide cream-coloured<br />
band across the mid-section <strong>of</strong> the body. It is 1<br />
cm long and appears in mid-summer.<br />
Satin Moth (Leucoma salicis): Larvae are defoliators <strong>of</strong><br />
poplars and willows. Adult moths are pure<br />
satin white. Caterpillars are black with red and<br />
white markings and grow up to 5 cm long.<br />
They appear in May and late July and<br />
skeletonize the foliage until fall.<br />
Cultural Management<br />
unit area if indicated)<br />
Control insects to reduce sooty mould. Successful insect<br />
control will prevent sooty mould. See the Ministry’s Home and<br />
Garden Guide for landscape tree recommendations.<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
SENATOR 70WP: 110 g<br />
Early spring applications at<br />
budbreak may be justified if trees<br />
are small enough to spray.<br />
Control is not usually<br />
required.<br />
This disease rarely<br />
requires control on larger<br />
trees in the nursery or<br />
landscape.<br />
No fungicides are specifically registered for this disease.<br />
Application <strong>of</strong> fungicides for leaf spot (above) may help to<br />
control this disease if applied before the disease is<br />
widespread.<br />
Management: Collect fallen leaves and compost, burn, or<br />
bury. This disease is very common in late summer on native<br />
poplar and cottonwood. It usually does not damage trees,<br />
although it can be unsightly on landscape and nursery trees.<br />
More severe damage can occur on the alternate hosts if grown<br />
nearby.<br />
Fungicides applied for leaf spot<br />
(above) should also help to<br />
control shoot blight. Apply at<br />
bud-break if needed.<br />
The fungus can overwinter<br />
on diseased shoots and<br />
leaves. Prune out and<br />
destroy affected shoots.<br />
Rake up and burn, bury or<br />
compost leaves in fall.<br />
Remove and burn badly<br />
infested trees and limbs.<br />
The boring grubs cannot<br />
be controlled. Insecticides<br />
are directed against adults<br />
and new, pre-boring<br />
grubs. See General Insect<br />
and Mite Management: Bark<br />
Beetles and Wood Borers,<br />
Chapter 11.<br />
AMBUSH 500EC: 7 mL<br />
BIOPROTEC CAF: 4 L/ha<br />
See General Insect and Mite Management: Caterpillars and Moths,<br />
Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 29
Pest Description<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Cultural Management<br />
PRUNUS - FLOWERING CHERRY, PLUMS, etc. (For Commercial Orchards -<br />
See BCMA Tree Fruit Production Guide)<br />
Diseases:<br />
Bacterial Canker, Blight, Blast, Leaf Shot-Hole and<br />
Spot (Pseudomonas syringae pv. syringae): This<br />
bacterial disease is very damaging at the Coast<br />
in cool, wet springs. It causes cankers,<br />
exudation <strong>of</strong> gum and dieback <strong>of</strong> girdled<br />
branches. Gumming occurs at margins <strong>of</strong><br />
cankers in spring, usually after a rain. Under<br />
wet conditions, numerous leaf spots are caused<br />
by rain-splashed bacteria. Spots <strong>of</strong>ten drop out<br />
leaving a “shot-hole”. Blossoms and new<br />
shoots may brown <strong>of</strong>f completely giving a<br />
“blasted” appearance. New infections cease<br />
once weather turns warm. See General Disease<br />
Management: Bacterial Blight / Canker, Chapter 9.<br />
Brown Rot (Monilinia spp.): This fungal disease<br />
causes blossom blight and dieback <strong>of</strong> new<br />
shoots in late spring, followed by fruit rot in<br />
summer. Fruit turn brown during ripening,<br />
later becoming mummified. Dead blossoms<br />
and fruit exhibit a brown, fuzzy mould in wet<br />
weather. The fungus overwinters on<br />
mummified fruit and in small cankers on<br />
infected twigs and at the base <strong>of</strong> buds. The<br />
disease is most severe in warm, wet conditions.<br />
In Coastal areas, symptoms tend to overlap<br />
with those <strong>of</strong> bacterial canker (see above),<br />
although brown rot infection tends to occur at<br />
warmer temperatures.<br />
Cherry Leaf Curl or “Witches’ Broom” (Taphrina<br />
cerasi): Large, broom-like tufts develop on<br />
branches at blossom time. These branches have<br />
few flowers and leaf out earlier than other<br />
branches. The brooms do not bear fruit and<br />
they get larger each year.<br />
Cherry Leaf Spot (Blumeriella jaapii; anamorph<br />
Coccomyces): Brown to purple leaf spots;<br />
smaller on sour cherry than on sweet cherry.<br />
Large areas <strong>of</strong> leaves may be killed. Spots <strong>of</strong>ten<br />
drop out leaving a shot-holed appearance.<br />
Spots may also occur on fruit stems causing<br />
drop. White spore masses <strong>of</strong> the fungus appear<br />
within the spots. Common in the Interior but<br />
rarely occurs at the Coast.<br />
COPPER SPRAY 50: 600 g<br />
Apply prior to fall rains and<br />
again when the majority <strong>of</strong><br />
leaves have fallen.<br />
Recommended to apply<br />
additional sprays immediately<br />
following pruning or grafting.<br />
Copper may cause leaf spot if<br />
applied under cool, cloudy<br />
conditions. To reduce injury, use<br />
the high rate for fall and delayed<br />
dormant applications and the<br />
low rate in the growing season.<br />
Obtain stock from sources<br />
believed to be free <strong>of</strong><br />
disease.<br />
‘Royal Ann’, ‘Bing’,<br />
‘Lambert’ and ‘Van’<br />
cherries are highly<br />
susceptible. Use Mazzard F-<br />
12-1 rootstock for cherries.<br />
Disinfect pruning tools<br />
between trees. Eliminate<br />
old, infected cherry trees<br />
from vicinity <strong>of</strong> fields<br />
where Prunus nursery stock<br />
is being grown.<br />
Apply at pink-bud stage. If wet weather occurs at this time,<br />
repeat sprays at 50% bloom and full bloom:<br />
BOTRAN: 1.75 kg/ha (peach)<br />
BRAVO 500: 5-9 L/ha<br />
CAPTAN 80-WP: 3.75-4.5 kg/ha<br />
FUNGINEX DC: 75 mL<br />
KUMULUS DF: 750 g<br />
ROVRAL WP & WDG: 1.5 kg/ha<br />
TOPAS 250E: 500 mL/ha<br />
Apply in all regular sprays except blossom:<br />
BORDEAUX: 200 g COPPER 53W + 400 g HYDRATED LIME<br />
Apply copper under fast drying conditions.<br />
Ornamentals only: DACONIL 2787F: 250 mL or DACONIL<br />
Ultrex: 150 g<br />
Remove mummified fruits from tree and ground during<br />
dormant season. Prune out cankered twigs.<br />
Refer to the Ministry’s Tree Fruit Production Guide for<br />
additional chemical control options.<br />
See Peach Leaf Curl, below.<br />
Prune out “witches’<br />
broom” 30 cm below point<br />
<strong>of</strong> infection. Remove old,<br />
infected trees from the<br />
nursery.<br />
COPPER SPRAY 50: 200 g + HYDRATED LIME: 400 g<br />
EQUAL 65WP: 2.25 kg/ha<br />
FERBAM 76 WDG: 175-200 g<br />
KUMULUS DF: 750 g<br />
TOPAS 250E: 500 mL/ha<br />
Make the first application at petal fall. In the 3 weeks prior to<br />
harvest make a 2nd and 3rd application at a 7-10 day interval.<br />
30 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Coryneum Blight, Shot-hole (Wilsonomyces<br />
carpophilus; anamorph Stigmina carpophila): This<br />
fungal disease infects apricots, cherries and<br />
peaches. Twigs develop small dark circular<br />
spots. Some become gummy. Small reddishbrown<br />
to purple spots appear on leaves and<br />
then drop out, leaving a shot-holed<br />
appearance. Spots also appear on peach and<br />
apricot fruit.<br />
Crown Gall (Agrobacterium tumefaciens): This bacterial<br />
disease causes galls to form on roots and stems.<br />
The bacteria can remain in the soil in the<br />
absence <strong>of</strong> a host for several years.<br />
Cytospora Canker (Cytospora spp.; teleomorph<br />
Leucostoma species): This fungal disease is<br />
important on stone fruits, particularly on<br />
peaches in the South Okanagan and can also<br />
occur in Coastal BC. Slightly sunken cankers<br />
are formed on the bark. Black, pimple-like<br />
fruiting bodies, which extrude white tendrils <strong>of</strong><br />
spores under wet conditions, can be seen in the<br />
cankers. The fungus also attacks apple and<br />
other ornamental trees and shrubs. Infection<br />
results from spores splashing on wounds<br />
caused by pruning, sunburn or breakage <strong>of</strong><br />
branches.<br />
Little Cherry Disease/Little Cherry Virus: Infected<br />
black cherries have small pointed, pinkishcoloured<br />
fruits with insipid flavour. On sour<br />
cherries, fruits are small, yellowish or pink and<br />
the tree has loss <strong>of</strong> vigour. Flowering cherries,<br />
such as ‘Kwansen’ and ‘Shir<strong>of</strong>ugen’, may be<br />
symptomless carriers <strong>of</strong> little cherry virus. The<br />
main vector is the apple mealy bug.<br />
Peach Leaf Curl (Taphrina deformans): This disease,<br />
which infects only peaches and nectarines, is<br />
most severe in wet areas. The fungus<br />
overwinters on bark and twigs. It infects buds<br />
during late winter as they are swelling. Leaves<br />
are yellow to reddish initially and become<br />
thickened and fleshy, later developing a dusty,<br />
white coating <strong>of</strong> spores. Infected leaves fall<br />
prematurely and new, healthy leaves may<br />
appear later in the summer.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Cultural Management<br />
unit area if indicated)<br />
COPPER 53W: 400 g<br />
Prune out diseased twigs<br />
COPPER SPRAY 50: 600 g during the dormant season.<br />
Apply before fall rains and<br />
again when the majority <strong>of</strong><br />
leaves have fallen. Copper may<br />
cause leaf spotting under cool,<br />
cloudy conditions.<br />
FLINT 50WG: 210-280g/ha<br />
ZIRAM 85W: 8 kg/ha<br />
Avoid planting susceptible species in beds known to be<br />
infested. Remove all galls when moving stock. Disinfect all<br />
tools and work areas with a strong bactericide when working<br />
with gall-infected material. Inspect roots and do not plant<br />
gall-infected material. See General Disease Management: Crown<br />
Gall, Chapter 9.<br />
Apply at leaf drop or in early<br />
spring before bud break:<br />
BRAVO 500: 5-7 L/ha<br />
COPPER SPRAY 50: 200 g<br />
COPPER 53W: 190 g<br />
Repeat before bud break in<br />
spring unless another dormant<br />
spray has been used.<br />
Apply by the end <strong>of</strong> January:<br />
FERBAM 76 WDG: 175-350 g<br />
Dormant:<br />
LIME SULPHUR: 10 L<br />
Verticillium Wilt (Verticillium spp.): See General Disease Management: Verticillium Wilt, Chapter 9.<br />
Minimize wounding<br />
especially during wet<br />
weather. Prune as late as<br />
possible in the dormant<br />
season. It is important to<br />
remove all cankered wood<br />
from the vicinity <strong>of</strong> the<br />
nursery or orchard.<br />
Whitening <strong>of</strong> the bark to<br />
prevent sunscald is also a<br />
useful preventive measure.<br />
Avoid excessive nitrogen or<br />
irrigation in the growing<br />
season.<br />
Use virus-tested stock for<br />
propagation <strong>of</strong> both sweet<br />
and flowering cherries.<br />
Refer to Little Cherry Control<br />
Regulations, Chapter 2, for<br />
restrictions on movement<br />
and production <strong>of</strong> cherries<br />
in the Little Cherry Control<br />
Areas <strong>of</strong> BC.<br />
Where practical, pick and<br />
destroy infected leaves<br />
before sporulation occurs in<br />
early summer.<br />
Fall sprays will also control<br />
Coryneum blight.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 31
Pest Description<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
PRUNUS LAUROCERASUS - CHERRY LAUREL<br />
Diseases:<br />
Leaf Spots, Shot-hole - Bacterial (Pseudomonas<br />
syringae pv. syringae), Fungal (Cercospora spp.<br />
and other fungi): The bacterium, Pseudomonas<br />
syringae, and several fungi can cause reddishbrown<br />
leaf spots that may fall out giving the<br />
leaf a shot-holed appearance. Identification <strong>of</strong><br />
the causal agent is <strong>of</strong>ten difficult, but may be<br />
necessary for selection <strong>of</strong> the proper chemical<br />
control. Fungal diseases are more common in<br />
the Interior and bacterial blight at the Coast.<br />
Insects:<br />
Cherry Bark Tortrix (Enarmonia formosana): The<br />
larvae live under the bark and show a<br />
preference for scar tissue from graft unions.<br />
Frass (excrement) and gum-like resin can be<br />
observed at the entrance <strong>of</strong> the tunnels. The<br />
larvae overwinter and pupate in the spring<br />
inside the tunnels. Moths have dark brown<br />
forewings with yellow-orange lines. They<br />
emerge in May and periodically through the<br />
summer.<br />
Cherry Ermine Moth: See MALUS: Apple Ermine Moth.<br />
Leafrollers: Larvae are green with black heads. They<br />
feed on leaves and fruit, and drop on silk<br />
threads when disturbed.<br />
Peach Tree Borer (Synanthedon excitiosa): It affects<br />
apricots, cherries, chokecherries, nectarines,<br />
peaches, plums and prunes. Females lay eggs<br />
near the soil line on tree trunks where, after<br />
hatching, the larvae tunnel under the bark.<br />
Larvae are cream colored with brown heads<br />
and reach up to 30 mm long. Adults are clearwinged<br />
moths around 25 mm long with yellow<br />
banded abdomens. Can girdle and kill young<br />
trees. Older trees are weakened and become<br />
susceptible to other pests.<br />
Pear Sawfly (Caliroa cerasi): Adult is a shiny black fly<br />
with four wings. Black slug-like larvae<br />
skeletonize leaves in summer.<br />
Apply fungicide or bactericide<br />
to protect new growth in<br />
spring.<br />
Fungal:<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
See General Disease Management:<br />
Bacterial Blight / Canker, Chapter<br />
9.<br />
Because <strong>of</strong> the long flight<br />
period <strong>of</strong> the moths and the<br />
bark-boring habit <strong>of</strong> the larvae,<br />
effective chemical controls have<br />
not been developed.<br />
Cultural Management<br />
Avoid overhead irrigation<br />
in the afternoon or evening.<br />
Destroy fallen leaves. Very<br />
susceptible varieties such as<br />
‘Zabeliana’ cannot be<br />
grown disease-free in<br />
containers under sprinkler<br />
irrigation. They can be more<br />
successfully grown in the<br />
field. They must not be<br />
subjected to daily<br />
sprinkling in the landscape<br />
and they should not be<br />
planted under any type <strong>of</strong><br />
cherry tree.<br />
Older infested trees should<br />
be cut down to reduce<br />
breeding <strong>of</strong> this insect.<br />
DIAZINON 50WSP or 50EC (cherries): 100 g or 100 mL<br />
DIPEL WP: 2.25-3.35 kg/ha<br />
DIPEL 2X DF: 1.125-1.675 kg/ha<br />
DOKTOR DOOM: 60-480 mL/0.4 ha<br />
IMIDAN 50-WP: 3.75 kg/ha<br />
ORTHENE 75% SP: Mist blower = 1,312 g/1,000 L; Hydraulic<br />
sprayer = 637 g/1,000 L<br />
SEVIN T&O: 230-350 mL<br />
Spray when bearing trees are in pink-bud stage.<br />
DECIS 5 EC: 6.8 mL<br />
ISOMATE-P PHEROMONE:<br />
250 to 625 dispensers/ha for<br />
peaches, nectarines and<br />
apricots. One dispenser per<br />
tree. Apply in the spring prior<br />
to moth emergence, one<br />
application can provide seasonlong<br />
control.<br />
MILLENIUM: 1 tray/9.4 L<br />
THIONEX 50 W: 150 g<br />
See General Insect and Mite<br />
Management: Sawflies, Chapter<br />
11.<br />
Install a metal cone-shaped<br />
collar around the base <strong>of</strong><br />
the tree before eggs are laid<br />
to prevent larvae from<br />
boring into the base <strong>of</strong> the<br />
tree. Kill larvae in tunnels<br />
by probing with a wire or<br />
by opening the tunnels to<br />
find and destroy them.<br />
Apply when damage is first<br />
noticed in spring and again<br />
in July-August.<br />
32 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
PSEUDOTSUGA - DOUGLAS FIR<br />
Diseases:<br />
Diaporthe Canker (Diaporthe lokoyae; anamorph<br />
Phomopsis lokoyae): This fungus infects new<br />
shoots. The sunken cankers are elliptical and<br />
differ in size. Larger cankers can be up to 75 cm<br />
long. They develop during the dormant season.<br />
Dieback occurs when a limb is girdled. Tiny,<br />
black fruiting bodies (pycnidia) are found in<br />
the cankered area.<br />
Douglas Fir - Cottonwood Rust (Melampsora<br />
occidentalis): Yellow rust pustules are present<br />
on underside <strong>of</strong> needles, which turn yellow<br />
and die prematurely. Cottonwood leaves<br />
develop angular, yellow spots on the upper leaf<br />
surface that correspond to yellow and brown<br />
rust pustules on the lower surface.<br />
Grey Mould/Seedling Blight (Botrytis cinerea):<br />
Individual new shoots wilt and turn brown<br />
early in the growing season, causing<br />
conspicuous blight in unusually wet springs.<br />
Needle Cast (Rhabdocline pseudotsugae): Yellow spots<br />
appear on current season needles in early fall.<br />
Spots enlarge the following spring and turn<br />
into purplish-brown bands in May or June.<br />
Spores shed from these bands infect newlyopening<br />
needles in spring. The old needles fall<br />
<strong>of</strong>f leaving a single year’s needles on the tree.<br />
Cool, wet weather promotes infection.<br />
Needle Cast (Rhizosphaera kalkh<strong>of</strong>fi): Small yellow to<br />
greyish-green, mottled spots appear on current<br />
year’s needles in late summer, particularly on<br />
lower branches. Spots then turn purplishbrown.<br />
See PICEA: Needle Cast for a full<br />
description <strong>of</strong> this disease.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Fungicides applied to control<br />
other diseases listed below will<br />
also help to prevent infection<br />
by this fungus.<br />
Cultural Management<br />
Keep trees healthy. Prune out<br />
infected limbs well below the<br />
canker. Remove prunings<br />
from the area and burn, bury<br />
or chip, since spores from<br />
dead, cankered limbs can<br />
cause new infections.<br />
Both hosts are required for<br />
survival <strong>of</strong> the rust.<br />
Susceptible cottonwoods<br />
include Populus trichocarpa,<br />
P. balsamifera and hybrid<br />
poplars. These should be<br />
removed from the<br />
perimeter <strong>of</strong> fields<br />
producing Douglas fir. See<br />
also POPULUS: Rust.<br />
See General Disease Management: Botrytis Blight and Storage<br />
Moulds, Chapter 9.<br />
BRAVO Ultrex 90 SDG: 1.3-2.7 kg/ha<br />
COPPER SPRAY 50: 400 g<br />
DACONIL 2787F: 2.4–4.8 L/ha<br />
DACONIL Ultrex: 1.45-2.9 kg/ha<br />
DITHANE DG, M-45 or WSP 80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Treat when new growth is 1-5 cm in length. Repeat sprays<br />
every 10-14 days in cool, wet springs.<br />
BANNER MAXX: 35 mL (for use<br />
on Christmas trees only)<br />
Fungicides applied for<br />
Rhabdocline Needle Cast (see<br />
above) will help to control this<br />
disease also.<br />
Seedling Blight (Sirococcus conigenus): See under PICEA and in General Disease Management: Sirococcus Blight, Chapter<br />
9.<br />
Swiss Needle Cast (Phaeocryptopus gaeumannii):<br />
Fungal fruiting bodies appear as rows <strong>of</strong> black,<br />
pinhead-like dots on the underside <strong>of</strong> needles.<br />
There may be defoliation <strong>of</strong> one- and two-yearold<br />
needles in early spring.<br />
Insects:<br />
Cooley Spruce Gall Adelgid (Adelges cooleyi): Insects<br />
attack both spruce and Douglas fir. On Douglas<br />
fir they are present as woolly aphids in spring.<br />
See under PICEA-SPRUCE.<br />
Fungicides applied for<br />
Rhabdocline Needle Cast (see<br />
above) will help to control this<br />
disease also.<br />
See General Insect and Mite Management: Aphids and Adelgids,<br />
Chapter 9.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 33
Pest Description<br />
Douglas Fir Needle Midge (Contarinia sp.): The adult<br />
is a small midge that emerges when buds are<br />
breaking. The fly lives for a few days; just<br />
enough time to mate and lay eggs. They<br />
deposit eggs in groups on expanding buds and<br />
new needles. The eggs hatch in a few days. The<br />
larvae penetrate and mine needles, and drop to<br />
the ground in the fall to overwinter. Even light<br />
infestations lower market value and<br />
appearance <strong>of</strong> Christmas trees. Moderate or<br />
heavy infestations cause serious defoliation.<br />
Infested needles become yellowed and angle<br />
sharply.<br />
Silverspotted Tiger Moth (Douglas Fir Webworm -<br />
Halisidota argentata): Newly-hatched larvae are<br />
greenish-brown, fuzzy and about 6 mm long.<br />
Later stages are up to 37 mm long, thickly<br />
haired and tufted with reddish-brown, yellow<br />
and black hairs. Larvae spin a tent or web<br />
around a branch and feed in or around the tent.<br />
PYRACANTHA - FIRETHORN<br />
Diseases:<br />
Fire Blight (Erwinia amylovora): New shoots wilt<br />
suddenly in spring, turning black/brown. The<br />
dead leaves hang down on infected twigs. It is<br />
uncommon in Coastal areas, but can occur<br />
during summer propagation in polyhouses.<br />
Scab (Venturia pyracanthae): Black scabs or blotches<br />
appear on leaves and berries.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DIPEL WP: 62.5 g<br />
Apply when larvae first appear<br />
in March and tent is still small.<br />
Repeat spray in two weeks if<br />
necessary.<br />
Cultural Management<br />
Christmas tree growers<br />
should use emergence<br />
cages placed on the<br />
ground to determine<br />
midge emergence.<br />
Treatments should be<br />
applied when the buds are<br />
stretching.<br />
Prune out and destroy<br />
tents when seen in fall or<br />
spring.<br />
See General Disease Management: Fire Blight, Chapter 9 and<br />
COTONEASTER: Fire Blight.<br />
BANNER MAXX: 14 mL<br />
DACONIL 2787F: 250 mL or DACONIL Ultrex: 150 g<br />
Spray when blossoms open and at 10-day intervals at least<br />
twice more during early part <strong>of</strong> growing season.<br />
Destroy all fallen leaves if practical. Appendix D contains a<br />
list <strong>of</strong> resistant varieties.<br />
PYRUS – PEAR (For Commercial Orchards - See BCMA Tree Fruit Production Guide)<br />
Diseases:<br />
Anthracnose Canker (Cryptosporiopsis curvispora): See under MALUS.<br />
European Canker (Nectria galligena): See under MALUS.<br />
Fire Blight (Erwinia amylovora): New shoots wilt<br />
suddenly in spring, turning black/brown. The<br />
dead leaves hang downward on affected twigs.<br />
This bacterial disease is not considered to be a<br />
problem in Coastal areas. In the Interior, it can<br />
spread quickly at temperatures above 18°C in<br />
wet weather, especially following hail damage.<br />
Symptoms can be confused with Pseudomonas<br />
blossom blast, which is more common on the<br />
Coast and occurs earlier in the spring.<br />
See General Disease<br />
Management: Fire Blight,<br />
Chapter 9.<br />
Prune out diseased branches<br />
at least 15 cm below the<br />
affected area in dormant<br />
season, or at least 30 cm<br />
below the affected area in the<br />
early growing season. ‘Bosc’<br />
is highly susceptible and<br />
whole branches may need to<br />
be removed.<br />
34 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Pear Trellis Rust (Gymnosporangium fuscum): Orangered<br />
spots with black centres appear on leaves in<br />
June-July. By late August, the spots thicken and<br />
spores emerge in spiky tufts from the lower leaf<br />
surface. Fruit and twig infections may occur on<br />
trees with large numbers <strong>of</strong> leaf infections. Juniper<br />
is the alternate host. Spores from juniper must reinfect<br />
pears each year, although in some cases<br />
repeating infections can occur from twig cankers.<br />
The disease is common in the Lower Mainland,<br />
but not in the Interior. A Domestic Movement<br />
Certificate is needed to transport pear nursery<br />
stock out <strong>of</strong> the Lower Mainland. See British<br />
Columbia Plant Protection Regulations, Chapter 2.<br />
Scab (Venturia pirina): See under MALUS.<br />
Insects and Mites:<br />
Pear Leaf Blister Mite and Pear Rust Mite (Eriophyes<br />
pyri and Epitrimerus pyri): Almost microscopic,<br />
white, worm-like mites produce blistering and<br />
russeting on leaves and fruit. The mite is within<br />
the blisters and is difficult to control during the<br />
growing season. Best control is achieved with a<br />
dormant spray.<br />
Pear Psylla (Psylla pyricola): Adults are green to<br />
brown and overwinter on the trees or on the<br />
ground and become active in March. Eggs are<br />
laid in spring before buds open during<br />
blossoming. Nymphs invade buds and feed on<br />
developing leaves and flowers. Later they<br />
move to leaves and live in honeydew drops.<br />
Summer eggs are laid on leaves. Three to five<br />
generations occur per season. Leaves blacken<br />
with sooty mould and fall <strong>of</strong>f.<br />
Not known to be a pest in Coastal nurseries.<br />
More common in Interior orchards.<br />
Pear Sawfly (Caliroa cerasi): Adult is a shiny, black fly<br />
with four wings. Black slug-like larvae<br />
skeletonize leaves in summer.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
NOVA 40W: 34 g<br />
Repeat at 14-day intervals. No<br />
more than 6 applications per<br />
year.<br />
CAPTAN 80 WDG: 120 g; do<br />
not use Captan on ‘Anjou’.<br />
EQUAL 65W: 3.25 kg/ha; do<br />
not use in the Interior where<br />
resistance is common.<br />
FERBAM 76 WDG: 200 g<br />
INSPIRE: 292 mL/ha<br />
KUMULUS DF: 400-750 g<br />
LIME SULPHUR: 125 mL<br />
MAESTRO 80DF: 3.75 kg/ha;<br />
do not use on ‘Anjou’.<br />
SULPHUR: See labels.<br />
Cultural Management<br />
Do not plant ornamental<br />
pears as landscape trees in<br />
the Lower Mainland. Avoid<br />
planting pear trees within 30<br />
m <strong>of</strong> susceptible junipers.<br />
Pick <strong>of</strong>f infected pear leaves<br />
as you see them. The leaves<br />
and fungus will die quickly if<br />
removed in mid-summer.<br />
In addition to the control<br />
measures used for apple scab,<br />
pear scab control also<br />
requires measures to reduce<br />
overwintering on twigs.<br />
Prune out severely infected<br />
twigs during dormant season.<br />
Apply dormant or delayeddormant<br />
lime sulphur.<br />
European canker can infect<br />
through scab lesions on<br />
twigs.<br />
See General Insect and Mite Management: Mites, Chapter 11.<br />
AGRI-MEK 1.9% EC: 20-40 mL + 0.25% PARAFFINIC SPRAY OIL<br />
DIAZINON 50WSP: 150 g + 1 L <strong>of</strong> HORTICULTURAL OIL<br />
DYNO-MITE or SANMITE: 28.4 g<br />
KUMULUS DF: 200 g<br />
True dormant stage only:<br />
LANDSCAPE OIL: 3 L<br />
LIME SULPHUR 23%: 10 L<br />
ACTARA 25 WG: 315-385 g/ha<br />
AGRI-MEK 1.9% EC: 20-40 mL + 0.25% PARAFFINIC SPRAY OIL<br />
DECIS 5 EC: 6.8-11.8 mL<br />
DIAZINON 50EC or 50WSP: 100 mL or 100 g<br />
IMIDAN 50-WP: 3.75 kg/ha<br />
INSECTICIDAL SOAP 47% or 50.5%: 2 L<br />
MALATHION 500 E: 125-250 mL<br />
POUNCE 384 EC: 17.5-35 mL. Use the low rate to control<br />
overwintering adults prior to bloom.<br />
RIPCORD 400 EC: 7.5 mL<br />
SEVIN T&O: 230-350 mL<br />
True dormant stage only:<br />
LANDSCAPE OIL: 2 L<br />
SUPERIOR 70 OIL: 2 L<br />
Treat when damage is first noticed in spring and again in July-<br />
August. See General Insect and Mite Management: Sawflies,<br />
Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 35
Pest Description<br />
QUERCUS - OAK<br />
Diseases:<br />
Anthracnose (Apiognomonia sp. (Discula quercina)):<br />
This disease is very similar to anthracnose <strong>of</strong><br />
Platanus. It is most damaging on white oak.<br />
Spots on leaves run together to form blotches<br />
along veins. Rain favours infection. Defoliation<br />
can occur. The disease is <strong>of</strong>ten worse on trees<br />
under stress and in years with warm, wet<br />
springs.<br />
Insects:<br />
Bruce Spanworm (Operophtera bruceata) and Winter<br />
Moth (Operophtera brumata): These loopers<br />
defoliate trees during May and early June.<br />
Jumping Gall Wasp (Neuroterus saltatorius): This<br />
wasp causes small, 1-1.5 mm, yellow galls on<br />
leaves <strong>of</strong> Garry oak. Galls are visible from June<br />
to September, accompanied by severe and<br />
chronic mid-summer leaf scorching. The wasp<br />
is known to occur only on Saltspring and<br />
southeast Vancouver Island.<br />
Oak Leaf Phylloxera (Phylloxera glabra; Phylloxera sp.):<br />
This small, yellow to orange, aphid-like insect<br />
is present throughout southern BC. It causes<br />
mid-summer leaf spotting, scorching and<br />
defoliation <strong>of</strong> Garry oak in landscape and<br />
nurseries. Trees may eventually die. Other<br />
ornamental oaks are also attacked but are not<br />
as severely affected.<br />
Oak Leaf Shredder (Croesia semipurpurana): Larval<br />
feeding produces numerous tiny holes in<br />
young foliage. The larvae then tie leaves<br />
together with silk webbing. Larvae pupate in<br />
the soil; adults emerge in summer and deposit<br />
eggs in bark <strong>of</strong> 2- and 3-year-old twigs. Several<br />
years <strong>of</strong> severe defoliation can kill a tree.<br />
RHAMUS - BUCKTHORN<br />
Diseases:<br />
Rot <strong>of</strong> Stem Cuttings (Pythium/Phytophthora spp.):<br />
Basal rot <strong>of</strong> stem cuttings and poor rooting.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Apply when buds begin to swell.<br />
Repeat sprays at 7-14 day<br />
intervals in wet springs.<br />
Cultural Management<br />
On small nursery trees, a<br />
fungicide spray program<br />
is recommended during<br />
the spring to prevent<br />
infection. Large trees can<br />
sustain severe disease in<br />
some years without<br />
permanent damage and<br />
spraying is usually<br />
impractical. See under<br />
PLATANUS.<br />
See General Insect and Mite Management: Bruce Spanworm and<br />
Winter Moth, Chapter 11.<br />
Nurseries:<br />
Apply a general systemic<br />
insecticide in mid-May. Contact<br />
the BCMA entomologist for<br />
specific recommendations.<br />
Landscape:<br />
No practical chemical control.<br />
ORTHENE 75% SP: Mist blower<br />
= 1,312 g/1,000 L; Hydraulic<br />
sprayer = 637 g/1,000 L<br />
RHODODENDRON and AZALEA (see AZALEA)<br />
RHUS - SUMAC<br />
Insects:<br />
Pear Leaf Blister Mite (Eriophyes pyri): Almost<br />
microscopic white worm-like mites produce<br />
blistering and russeting on leaves.<br />
Several naturallyoccurring<br />
predators and<br />
parasitic insects feed on<br />
the gall wasp.<br />
For nurseries, see General<br />
Insect and Mite<br />
Management: Aphids,<br />
Chapter 11. It is not<br />
usually practical to treat<br />
large landscape trees.<br />
Rogue out trees showing<br />
severe symptoms in new<br />
plantations.<br />
See General Disease Management: Damping Off and Stem Rot <strong>of</strong><br />
Cuttings, Chapter 9.<br />
See General Insect and Mite<br />
Management: Mites,<br />
Chapter 11.<br />
36 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
ROBINIA<br />
Diseases:<br />
Fusarium Canker (Fusarium spp.): Several Fusarium<br />
species can cause cankers and wilting<br />
symptoms on locust.<br />
ROSA – ROSE<br />
Diseases:<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
Dark brown, sunken spots appear on leaf and<br />
flower stalks and calyx parts. Flower buds die<br />
without opening. Black streaks appear on oneyear-old<br />
stems. The disease commonly occurs<br />
during cool, wet weather in spring.<br />
Black Spot (Diplocarpon rosae): Black to reddishbrown<br />
spots with smooth or irregular,<br />
“fringed” edges are visible on both sides <strong>of</strong> the<br />
leaf. Leaves yellow and drop. Spots can<br />
resemble those caused by downy mildew (see<br />
below).<br />
Brand Canker (Coniothyrium spp.): This fungal<br />
disease causes small, longitudinal splits in the<br />
bark, through which tiny, black, fungal fruiting<br />
bodies protrude. It <strong>of</strong>ten affects plants that are<br />
under stress or damaged by other factors.<br />
Brown Canker (Cryptosporella spp.): This canker has a<br />
light brown centre with a purple margin.<br />
Yellow to brown spores exude from the canker<br />
in damp weather.<br />
Crown Canker (Cylindrocladium scoparium): This<br />
disease is primarily a greenhouse problem. It<br />
has rarely been found in BC: once on imported<br />
bareroot stock from the Southern US, where the<br />
disease occurs in fields. The bark is blackened<br />
and water-soaked at the graft union. Canes<br />
become girdled and produce few and inferior<br />
blooms.<br />
Crown Gall (Agrobacterium tumefaciens): Galls appear<br />
on lower stems and roots.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER SPRAY 50: 600 g; apply<br />
once in October and again in<br />
January.<br />
BANNER MAXX: 33 mL<br />
CAPTAN 50-WP: 200-250 g<br />
CAPTAN 80-WP: 125-150 g<br />
CAPTAN 80 WDG: 120-140 g<br />
COMPASS 50WG: 15-20 g<br />
COPPER 53W: 560 g<br />
DACONIL 2787F: 180 mL<br />
DACONIL Ultrex: 110 g<br />
EAGLE WSP T&O: 30 g<br />
FUNGINEX DC: 100 mL<br />
NOVA 40W: 34 g<br />
PHYTON 27: 390 mL<br />
RHAPSODY: 1-2 L<br />
SENATOR 70WP: 50-75 g<br />
PHYTON 27: 125-400 mL<br />
(miniature roses)<br />
Cultural Management<br />
Cut out and burn or bury<br />
infected plant parts.<br />
See General Disease<br />
Management: Bacterial<br />
Blight / Canker, Chapter 9.<br />
Remove infected leaves.<br />
Water during the day so that<br />
leaves dry <strong>of</strong>f before sunset.<br />
Rake up and compost fallen<br />
leaves and apply lime<br />
sulphur during dormant<br />
season. Protect young leaves<br />
on susceptible varieties before<br />
infection with the other<br />
fungicides listed. For resistant<br />
varieties see Appendix J. For<br />
landscape and home garden<br />
control see the Ministry’s<br />
Home & Garden Pest<br />
Management Guide for British<br />
Columbia.<br />
Prune out diseased canes in<br />
early spring. Disinfect<br />
pruning tools between<br />
bushes. Avoid leaving large<br />
pruning stubs.<br />
Same as for Brand Canker<br />
(see above).<br />
Plant new stock in a sterile<br />
growing medium. Do not<br />
import stock from areas<br />
where the disease is known to<br />
occur in production fields.<br />
The fungus is soil-borne once<br />
it is introduced.<br />
See General Disease Management: Crown Gall, Chapter 9.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 37
Pest Description<br />
Downy Mildew (Peronospora sparsa): Infection by<br />
wind-blown sporangia produced by the<br />
organism cause reddish-purple leaf spots to<br />
appear on the upper leaf surface during cool,<br />
wet weather. Infected leaves yellow and drop,<br />
leading to poor plant vigour and growth.<br />
Disease symptoms resemble those caused by<br />
crown gall, nutritional or environmental factors<br />
and even black spot. The fungus can be<br />
systemic in infected plants, which may not<br />
show symptoms in the greenhouse, so is <strong>of</strong>ten a<br />
problem in propagation nurseries.<br />
Powdery Mildew (Sphaerotheca spp.): A white,<br />
powdery growth appears on leaves. Young<br />
leaves curl and are more purplish than normal.<br />
Rose Graft Canker (Coniothyrium rosarum): Cankers<br />
develop in forcing beds at the graft union.<br />
Canes die when the canker has encircled the<br />
graft.<br />
Rust (Phragmidium spp.): Rusty yellow and brown<br />
spots appear on leaves and stems.<br />
Stem Canker (Leptosphaeria spp.): Black spots and<br />
stem cankers form, <strong>of</strong>ten at tips where canes<br />
have been pruned back.<br />
Viruses:<br />
Mosaic: Chlorotic areas appear along midribs <strong>of</strong><br />
leaflets and leaves may be distorted. Infected<br />
plants may do well until stressed, then can<br />
quickly drop leaves and decline.<br />
Streak: The streak virus causes brown rings and<br />
brown vein-banding on fully expanded leaves<br />
and brownish or greenish rings on canes.<br />
Transmitted by grafting.<br />
Insects:<br />
Rose Midge (Dasineura rhodophaga): Larval (maggot)<br />
feeding occurs within the emerging leaf and<br />
flower buds, which causes the buds to wither<br />
and turn black. Midge feeding can cause<br />
complete failure <strong>of</strong> a bloom cycle. Peak injury<br />
occurs from mid-June to early July, and in late<br />
August/September.<br />
Sawfly (Rose Slug) (Endelomyi aethiops): The larval<br />
stage <strong>of</strong> the rose slug feeds only on roses. It<br />
skeletonizes the upper surface <strong>of</strong> leaves. The<br />
larva has a brown head and pale-green body<br />
that is up to 13 mm long. It moves to the soil in<br />
mid-summer to overwinter and pupate the<br />
following spring. There is only one generation<br />
per year.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER 53W: 560 g<br />
Cultural Management<br />
Management:<br />
In the polyhouse, monitor plants and remove infected leaves;<br />
control humidity; clean up crop debris at the end <strong>of</strong> the season;<br />
alternate crops if possible.<br />
In the nursery, avoid overhead watering in the evening.<br />
Some <strong>of</strong> the most popular roses, including ‘Austin’,<br />
‘Meidiland’ and mini-roses are highly susceptible. Climbing<br />
roses are <strong>of</strong>ten infected but tolerant <strong>of</strong> the disease, which<br />
produces only mild leaf spotting. However, they are a source<br />
<strong>of</strong> infection for other roses in the nursery and landscape.<br />
See General Disease Management: Powdery Mildew, Chapter 9.<br />
For resistant varieties see Appendix J.<br />
See General Disease<br />
Management: Rust, Chapter 9.<br />
Use disease-free wood for<br />
grafting. Rogue out diseased<br />
plants.<br />
Remove all infected<br />
overwintering leaves. For<br />
resistant varieties see<br />
Appendix J.<br />
See Brand Canker (above).<br />
Sterilize pruning tools.<br />
Provide good growing<br />
conditions.<br />
Use virus-free rootstocks and scionwood for propagation.<br />
Many roses will sustain some mosaic virus infection without<br />
serious injury, unless grown under stressful conditions. Water<br />
and fertilize to promote healthy, vigorous plants.<br />
Use virus-free rootstocks and<br />
scionwood for propagation.<br />
ORTHENE 75% SP: Mist<br />
blower = 1,312 g/1,000 L;<br />
Hydraulic sprayer = 637<br />
g/1,000 L<br />
See General Insect and Mite Management: Sawflies, Chapter 11.<br />
Thrips: Elongate, very small insects. Cause bronzing and drying <strong>of</strong> leaves and petals. Buds turn black and fail to open.<br />
See General Insect and Mite Management: Thrips, Chapter 11.<br />
38 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
SALIX - WILLOW<br />
Diseases:<br />
Blight (Marssonina salicicola, Septoria spp. and other<br />
fungi): These fungi overwinter as twig cankers.<br />
During wet spring weather, new leaves and<br />
shoots become infected. Under severe<br />
conditions, defoliation and extensive twig<br />
death occurs.<br />
Insects:<br />
Alder Flea Beetle (Altica ambiens ulni): The beetle is 6<br />
mm long, metallic green to blue with yellow<br />
legs. The adult and larval stages skeletonize<br />
leaves, but seldom cause serious injury.<br />
Aphids: A small to medium-sized, light green or<br />
yellow aphid sucks sap from leaves. A large,<br />
black aphid feeds on the bark <strong>of</strong> twigs. Large<br />
numbers produce much honeydew and attract<br />
wasps.<br />
Poplar and Willow Borer (Cryptorhynchus lapathi):<br />
The adult beetle is 6 mm long, dark brown,<br />
mottled, with light brown, grey, and pink<br />
scales. Larvae feed in s<strong>of</strong>t tissue <strong>of</strong> inner bark<br />
and sapwood, especially at the base <strong>of</strong> the tree,<br />
which they kill.<br />
Satin Moth (Leucoma salicis): The larvae are<br />
defoliators <strong>of</strong> cottonwood, poplar and willow,<br />
and occasionally attack oak and aspen.<br />
SKIMMIA<br />
Diseases:<br />
Black Root Rot (Thielaviopsis basicola): T. basicola is a<br />
soil-inhabiting fungus that causes root rot on a<br />
broad range <strong>of</strong> ornamental plants. The disease<br />
is favoured by wet and warm (12-18 o C) soils.<br />
The symptoms include yellowing <strong>of</strong> foliage,<br />
branch dieback, and blackened areas on roots.<br />
SORBUS - MOUNTAIN ASH<br />
Diseases:<br />
Apple Scab (Venturia inaequalis): This fungus causes<br />
scab (black spots) on leaves and fruit. Leaves<br />
are curled and distorted. New infections occur<br />
whenever there is a moderate to prolonged<br />
rainy period. The same fungus causes apple<br />
scab.<br />
Fire Blight (Erwinia amylovora): New shoots wilt<br />
suddenly in late spring and turn black or<br />
brown. Dead leaves hang downward on<br />
infected twigs. It is not considered to be a<br />
problem in Coastal areas.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
No fungicides are registered<br />
for control <strong>of</strong> these diseases<br />
on willow.<br />
Cultural Management<br />
In nurseries, prune and burn<br />
diseased twigs at least twice<br />
per year. See under<br />
POPULUS.<br />
See General Insect and Mite Management: Aphids, Chapter 11.<br />
DURSBAN WSP: 44.8 g See under POPULUS and in<br />
PRO DURSBAN TURF: 50 mL General Insect and Mite<br />
Management: Bark Beetles and<br />
Wood Borers, Chapter 11.<br />
See under POPULUS and in General Insect and Mite<br />
Management: Caterpillars and Moths, Chapter 11.<br />
SENATOR 70WP: 65-85 g<br />
Rake and destroy fallen<br />
leaves. Control scab on apples<br />
if grown nearby (see under<br />
MALUS).<br />
See General Disease Management: Fire Blight, Chapter 9.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 39
Pest Description<br />
Mites:<br />
Pearleaf Blister Mite (Phytoptus pyri): The mite is a<br />
tiny, elongated, worm-like pest, about 0.2 mm<br />
long. They overwinter beneath outer bud<br />
scales. Eggs are deposited in spring in leaf galls<br />
that develop as a result <strong>of</strong> feeding and<br />
irritation. Small, brown blisters appear on<br />
lower surfaces <strong>of</strong> leaves in spring.<br />
SYRINGA - LILAC<br />
Diseases:<br />
Bacterial Blight (Pseudomonas syringae pv. syringae):<br />
Dark black streaks appear on young shoots or<br />
on one side <strong>of</strong> a shoot in early spring. Leaf<br />
spots are brown, <strong>of</strong>ten with a yellow halo.<br />
Flowers wilt and turn brown. Buds are<br />
blackened. Rainy springs favour disease.<br />
Powdery Mildew (Microsphaera spp.): A white,<br />
powdery growth appears on leaves usually late<br />
in the growing season.<br />
Insects:<br />
Ash and Lilac Borer (Podosesia syringae): See under FRAXINUS - ASH<br />
Leafminer (Caloptilia syringella): The adult is a small,<br />
slender grey moth. It begins the season as a<br />
leafminer in late May, just before blossom time.<br />
The mines may run together to form a blotch.<br />
The larva forms a cocoon within the fold <strong>of</strong> a<br />
leaf where it overwinters.<br />
Oyster Shell Scale (Lepidosaphes ulmi): This is the<br />
most common scale attacking lilac. It is<br />
identified by its oyster-like appearance.<br />
TAXUS - YEW<br />
Diseases:<br />
Root Rot (Phytophthora sp.)<br />
THUJA - RED CEDAR, ARBORVITAE<br />
Diseases:<br />
Armillaria Root Rot (Armillaria spp.): Branches turn<br />
brown, <strong>of</strong>ten starting on one side <strong>of</strong> the tree.<br />
Examination reveals root rot and decay at the<br />
base <strong>of</strong> the trunk.<br />
See General Disease Management: Root Rot Caused<br />
by Armillaria, Chapter 9.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Cultural Management<br />
See General Insect and Mite Management: Mites, Chapter 11.<br />
See General Disease Management: Bacterial Blight/Canker,<br />
Chapter 9.<br />
See General Disease Management: Powdery Mildew, Chapter 9.<br />
See General Insect and Mite Management: Leafminers / Needle<br />
Miners, Chapter 11.<br />
See General Insect and Mite Management: Scales, Chapter 11.<br />
See General Disease Management: Root Rots Caused by<br />
Phytophthora and Pythium, Chapter 9.<br />
No chemical control.<br />
Management: Avoid growing Thuja in soils recently cleared<br />
<strong>of</strong> native forest vegetation. Rogue out and burn diseased<br />
plants taking care to remove all traces <strong>of</strong> tree roots and fungal<br />
“rhizomorphs” before re-planting with resistant species. For a<br />
list <strong>of</strong> resistant plants see Appendix M.<br />
40 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
Berckmann’s Blight / Seiridium Blight / Coryneum<br />
Canker (Seiridium spp., teleomorph Coryneum<br />
berckmannii): Severe twig and branch canker<br />
occurs only on Platycladus orientalis (formerly<br />
Thuja orientalis). Foliar blight can also occur on<br />
Thuja plicata and Chamaecyparis spp. Foliage<br />
looks greyish and infected twigs dieback.<br />
Young twig tips are infected, and the disease<br />
progresses inward on the tree. Spores infect<br />
twigs in late September but disease symptoms<br />
may not be apparent until the following spring.<br />
Tiny, black, fungal fruiting bodies are found in<br />
late summer/fall where twigs and branches are<br />
girdled.<br />
Cedar Flagging (physiological): Common on Thuja<br />
plicata (western red cedar). In late summer,<br />
patches <strong>of</strong> foliage turn yellow to reddish-brown<br />
on branches scattered about the tree.<br />
Foliar Blight/Dieback (Kabatina thujae): This disease<br />
affects Thuja occidentalis and Chamaecyparis spp.,<br />
causing leaf and shoot dieback in spring. It is a<br />
sign that the plants are not growing well.<br />
Keithia Blight (Didymascella thujina): Tiny, circular,<br />
brown to black, fungal fruiting bodies appear<br />
on scale leaves in late spring. The leaves then<br />
turn brown and affected areas fall out. Later,<br />
infected leaves drop, leaving branches with a<br />
sparse or bare appearance. Dormant spores<br />
adhering to the foliage in the fall can germinate<br />
and cause new infections during propagation.<br />
Leaf Browning/Purpling (Environmental): Foliage<br />
takes on an overall brownish or purplish colour<br />
in early spring. This colour change may occur<br />
rapidly. Healthy plants will green-up as the<br />
growing season progresses.<br />
Note: During flowering, some varieties may<br />
exhibit an overall reddish-purple colour. The<br />
colour may become suddenly more noticeable<br />
in years with more intense flowering.<br />
Insects and Mites:<br />
Cypress Tip Moth (Leafminer) (Argyresthia<br />
cupressella): Adult moths are silvery-tan in<br />
colour and are active in early June. Eggs are<br />
inserted into the green tips <strong>of</strong> one and twoyear-old<br />
twigs. The larvae tunnel into leaf<br />
scales and remain there until the next spring.<br />
Infested twigs turn yellow, then brown in late<br />
winter. A cocoon is spun around the foliage in<br />
early June <strong>of</strong> the second year for the pupal<br />
stage. Two to three weeks later, adults emerge.<br />
Mites: Damage usually occurs first at the bottom <strong>of</strong><br />
the plant and on the south side. Monitor by<br />
gently shaking the foliage above a sheet <strong>of</strong><br />
white paper.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
COPPER SPRAY 50: 400 g<br />
DITHANE DG, M-45 or WSP<br />
80WP: 275-350 g<br />
PENNCOZEB 80WP: 275-350 g<br />
Spray twice every fall and<br />
again in spring to protect new<br />
foliage.<br />
COPPER SPRAY 50: 400 g<br />
Apply once in the fall and<br />
every 2-3 weeks in the spring<br />
to protect new growth.<br />
Treat at least 3 times between<br />
March and mid-June.<br />
See General Disease<br />
Management: Keithia Blight,<br />
Chapter 9.<br />
MALATHION 500E: 250 mL<br />
In late April, mid-June and<br />
early July, spray to control<br />
larvae outside the foliage or<br />
moths before egg laying.<br />
Cultural Management<br />
Prune out affected branches<br />
and twigs. This disease is the<br />
main limiting factor to the<br />
successful growing <strong>of</strong> P.<br />
orientalis in Coastal BC.<br />
Dying twigs are <strong>of</strong>ten<br />
infected by secondary fungi<br />
so a laboratory diagnosis is<br />
<strong>of</strong>ten needed to confirm this<br />
disease.<br />
A natural occurrence; not<br />
damaging to the tree. May be<br />
more severe in droughty<br />
years.<br />
Examine soil for correct pH,<br />
nutrient levels and drainage.<br />
Avoid overhead watering.<br />
Irrigate early in the day.<br />
Avoid overhead watering <strong>of</strong><br />
Thuja plicata. T. plicata<br />
‘Atrovirens’ and ‘Excelsa’ are<br />
especially susceptible. Locate<br />
nursery beds <strong>of</strong> these varieties<br />
away from mature T. plicata<br />
windbreaks. Do not propagate<br />
from infected plants.<br />
Cold temperatures in winter<br />
and early spring, rather than<br />
drought, are responsible for<br />
the temporary leaf browning.<br />
Provision for shelter or<br />
windbreaks may help. T.<br />
occidentalis ‘Smaragd’ is less<br />
susceptible than other<br />
varieties.<br />
See General Insect and Mite Management: Mites, Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 41
Pest Description<br />
Redwood Bark Beetle (Phloeosinus sequoiae): The<br />
beetle commonly attacks weakened, dying or<br />
dead trees. The female beetle will bore into the<br />
inner bark and lay about 50 eggs. The emerged<br />
larvae feed in the sapwood and phloem. It<br />
overwinters as an adult or larva. Adults emerge<br />
in the summer and feed on small branches <strong>of</strong><br />
cedar and cypress, which can lead to flagging.<br />
Root Weevils: Adults may girdle twigs a few<br />
centimeters from tips. Tips turn brown making<br />
the tree unmarketable. Serious damage may<br />
occur on landscape plantings also.<br />
TILIA – LINDEN<br />
Diseases:<br />
Sooty Mould: Black mould grows on aphid secretions<br />
on leaves.<br />
Mites:<br />
Gall Mite (Phytoptus tiliae): Mites form red to<br />
greenish, pocket-like galls on the upper surface<br />
<strong>of</strong> leaves. Galls are about 5 mm long. This is a<br />
pest <strong>of</strong> T. cordata.<br />
TSUGA - HEMLOCK<br />
Diseases:<br />
Botrytis Blight (Botrytis cinerea): Botrytis causes a<br />
foliar blight <strong>of</strong> seedlings and container-grown<br />
plants in humid conditions.<br />
Tip Blight (Sirococcus conigenus): Death <strong>of</strong> young<br />
shoots, <strong>of</strong>ten forming a “hook” at the tip. Also<br />
causes seed decay and seedling blight. See<br />
under PICEA.<br />
Insects:<br />
Hemlock Woolly Adelgid (Adelges tsugae): This<br />
sucking insect appears as white, cottony puffs<br />
on the bark and base <strong>of</strong> needles. Infestation<br />
<strong>of</strong>ten leads to the production <strong>of</strong> abundant<br />
black, sooty mould. Premature needle drop<br />
may occur.<br />
See Comment 30 in Federal Plant Quarantine<br />
Regulations in Chapter 2.<br />
Hemlock Looper (Lambdina fiscellaria): Pale yellow<br />
caterpillars, up to 25 mm long, with a double<br />
row <strong>of</strong> small black dots along body, cause<br />
severe defoliation <strong>of</strong> outer shoots and twigs.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
Cultural Management<br />
unit area if indicated)<br />
See General Insect and Mite Management: Bark Beetles and Wood<br />
Borers, Chapter 11.<br />
See General Insect and Mite Management: Root Weevils, Chapter<br />
11.<br />
Control aphids to reduce sooty mould. See General Insect and<br />
Mite Management: Aphids and Adelgids, Chapter 11.<br />
Dormant season only:<br />
DORMANT OIL: 2 L<br />
See General Disease Management: Botrytis Blight and Storage<br />
Moulds, Chapter 9.<br />
See General Disease Management: Sirococcus Blight, Chapter 9.<br />
INSECTICIDAL SOAP 47% or<br />
50.5%: 2 L; spray after May 1<br />
LANDSCAPE OIL: 1-2 L to<br />
control eggs, nymphs and<br />
adults<br />
See General Insect and Mite<br />
Management: Woolly Adelgids,<br />
Chapter 11.<br />
FORAY 48BA: 2.4-3.2 L/ha<br />
THURICIDE 48LV: 160-240<br />
mL<br />
Nitrogen fertilization has<br />
been shown to enhance<br />
adelgid survival and negate<br />
pest control measures. If this<br />
insect is a problem, reduce<br />
nitrogen fertilization as much<br />
as possible.<br />
See General Insect and Mite<br />
Management: Caterpillars and<br />
Moths, Chapter 11.<br />
42 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide
Pest Description<br />
ULMUS - ELM<br />
Diseases:<br />
Dutch Elm Disease (Ceratocystis ulmi ): BC is free <strong>of</strong><br />
Dutch Elm Disease, which is spread by bark<br />
beetles, such as the Native and European Elm<br />
Bark Beetles. The vectors do occur in BC.<br />
Beetles acquire the fungus in the fall when they<br />
tunnel under the bark <strong>of</strong> infected branches to<br />
breed. They spread the pathogen when they<br />
emerge and feed on new, young twigs. The first<br />
symptoms <strong>of</strong> disease are wilt and dieback <strong>of</strong><br />
branches in mid-summer, <strong>of</strong>ten on only one<br />
side <strong>of</strong> the tree. Dark streaks can be found in<br />
the sapwood <strong>of</strong> infected branches. American<br />
elm is highly susceptible; Siberian and Chinese<br />
elm may become infected but do not wilt and<br />
die, so these resistant species rarely transmit<br />
the fungus. Other fungal diseases may cause<br />
branch dieback on elm with similar symptoms.<br />
Wet Wood or Slime Flux (Erwinia nimmipressuralis,<br />
and other bacteria): This bacterium is an invader<br />
<strong>of</strong> old, weakened or damaged trees and is a<br />
sign <strong>of</strong> other injury. It causes slimy, smelly<br />
cankers on trunks and branches and/or<br />
discolouration <strong>of</strong> interior wood. Exudate runs<br />
down the trunk causing further discolouration<br />
<strong>of</strong> the bark and attracts insects. It commonly<br />
affects old poplars, horse chestnuts and maples.<br />
Insects:<br />
Elm Leaf Beetle (Xanthogaleruca luteola): Attacks all<br />
elm species. The black, grub-like, larvae<br />
skeletonize the lower side <strong>of</strong> the leaf. Can lead<br />
to premature leaf drop. In the spring, the adult<br />
beetles lay yellow eggs in clusters on the<br />
underside <strong>of</strong> leaves. Larvae pupate on the<br />
ground at the base <strong>of</strong> the tree or in bark<br />
crevices. Adult beetles leave the tree to find a<br />
suitable overwintering site in the fall.<br />
European Elm Bark Beetle (Scolytus multistriatus): See<br />
Dutch Elm Disease (above).<br />
Woolly Apple Aphid (Eriosoma larigerum): This aphid<br />
causes clusters <strong>of</strong> rolled, twisted, and dwarfed<br />
leaves at the growing tip <strong>of</strong> elm shoots. Eggs<br />
overwinter on elm. After hatching in the<br />
spring, the insect then moves to apple, where it<br />
feeds on leaves and roots. It is present all<br />
summer.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
Tree Injection:<br />
Cultural Management<br />
ARBOTECT 20-S: See product label for application rate, etc.<br />
To control the disease-vectoring beetle, see European Elm Bark<br />
Beetle (below).<br />
Management: BC and Alberta remain free <strong>of</strong> Dutch Elm<br />
Disease. Rapid identification and removal <strong>of</strong> infected trees<br />
before beetles can breed in dead branches is essential to<br />
prevent its spread. Contact the Pacific Forestry Centre,<br />
Victoria, the Canadian Food Inspection Agency, or your local<br />
BCMA <strong>of</strong>fice immediately, if you observe wilt disease<br />
symptoms on an Ulmus tree. Do not bring Ulmus or Zelkova<br />
into BC. See British Columbia Plant Protection Regulations,<br />
Chapter 2 for information on the voluntary nursery<br />
certification program for the disease. Nurseries, parks and<br />
landscapers are advised to monitor American elm for dieback<br />
and prune out any dead or dying elm branches in the<br />
dormant season to prevent beetle breeding.<br />
Affected trees may die<br />
quickly, or limb by limb, and<br />
are a risk to fall down. Trees<br />
may be cleaned up to some<br />
extent by drilling holes just<br />
below the affected area and<br />
inserting plastic pipe to drain<br />
exudate from the trunk. An<br />
infected tree will eventually<br />
have to be cut down.<br />
ACECAP 97: for rate, see label or Aphids and Adelgids,<br />
Chapter 11.<br />
CONSERVE or SUCCESS 480 SC: 2.5 mL<br />
ENTRUST 80 W: 1.5 g<br />
ORTHENE 75% SP: Mist blower = 1,312 g/1,000 L; Hydraulic<br />
sprayer = 637 g/1,000 L (do not apply to American elms)<br />
THIONEX EC: 125-175 mL<br />
THIONEX 50 W: 100 g<br />
SEVIN T&O: 230-350 mL<br />
Nursery: Apply insecticides to prevent beetle feeding. Follow<br />
a regular spraying and monitoring program.<br />
ACECAP 97: for rate, see label or Aphids and Adelgids,<br />
Chapter 11.<br />
INSECTICIDAL SOAP 47% or 50.5%: 2 L<br />
POUNCE 384 EC: 9 mL<br />
Greenhouse only:<br />
IMPOWER 60WP: See label.<br />
See General Insect and Mite Management: Aphids and Adelgids,<br />
Chapter 11.<br />
Nursery Production Guide <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> • 43
Pest Description<br />
VIBURNUM<br />
Diseases:<br />
Powdery Mildew (Microsphaera spp.): Leaves become<br />
covered with white, powdery growth in late<br />
summer. The same fungus infects a wide range<br />
<strong>of</strong> woody, deciduous hosts.<br />
Insects:<br />
Viburnum Leaf Beetle (Pyrrhalta viburni): The larvae<br />
and adults both cause severe leaf<br />
skeletonization and defoliation <strong>of</strong> ornamental<br />
viburnums. Viburnum opulus is a preferred<br />
host, but it also causes moderate to slight injury<br />
on V. dentatum, V. lantana, V. tinus and V.<br />
trilobum. The viburnum leaf beetle has one<br />
generation per year. It overwinters as eggs,<br />
which are usually deposited in a straight row<br />
on the lower surface <strong>of</strong> 1- or 2-year-old twigs.<br />
The eggs hatch in the spring and the larvae<br />
begin to feed. In early summer, the larvae drop<br />
to the ground to pupate. Adult beetles emerge<br />
one month later. Female beetles will lay up to<br />
500 eggs from late summer to the first frost.<br />
Chemical Control<br />
(rate per 100 L water; or per<br />
unit area if indicated)<br />
DACONIL 2787F: 250 mL<br />
DACONIL Ultrex: 150 g<br />
ACTARA 25 WG: 280 g/ha<br />
CONSERVE 480 SC: 25<br />
mL/ha<br />
Cultural Management<br />
Fungicide applications are<br />
not usually warranted on<br />
landscape plants. Sulphur<br />
should not be used on<br />
Viburnum. See General Disease<br />
Management: Powdery Mildew,<br />
Chapter 9.<br />
To manage this pest prune<br />
out and destroy infested<br />
twigs after egg laying has<br />
stopped in the fall.<br />
See Appendix K for<br />
information on the<br />
susceptibility <strong>of</strong> Viburnum<br />
species to the viburnum leaf<br />
beetle.<br />
44 • <strong>Pests</strong> <strong>of</strong> <strong>Specific</strong> <strong>Crops</strong> Nursery Production Guide