Pests of Specific Crops

Pest Description
Coryneum Blight, Shot-hole (Wilsonomyces
carpophilus; anamorph Stigmina carpophila): This
fungal disease infects apricots, cherries and
peaches. Twigs develop small dark circular
spots. Some become gummy. Small reddishbrown
to purple spots appear on leaves and
then drop out, leaving a shot-holed
appearance. Spots also appear on peach and
apricot fruit.
Crown Gall (Agrobacterium tumefaciens): This bacterial
disease causes galls to form on roots and stems.
The bacteria can remain in the soil in the
absence of a host for several years.
Cytospora Canker (Cytospora spp.; teleomorph
Leucostoma species): This fungal disease is
important on stone fruits, particularly on
peaches in the South Okanagan and can also
occur in Coastal BC. Slightly sunken cankers
are formed on the bark. Black, pimple-like
fruiting bodies, which extrude white tendrils of
spores under wet conditions, can be seen in the
cankers. The fungus also attacks apple and
other ornamental trees and shrubs. Infection
results from spores splashing on wounds
caused by pruning, sunburn or breakage of
branches.
Little Cherry Disease/Little Cherry Virus: Infected
black cherries have small pointed, pinkishcoloured
fruits with insipid flavour. On sour
cherries, fruits are small, yellowish or pink and
the tree has loss of vigour. Flowering cherries,
such as ‘Kwansen’ and ‘Shirofugen’, may be
symptomless carriers of little cherry virus. The
main vector is the apple mealy bug.
Peach Leaf Curl (Taphrina deformans): This disease,
which infects only peaches and nectarines, is
most severe in wet areas. The fungus
overwinters on bark and twigs. It infects buds
during late winter as they are swelling. Leaves
are yellow to reddish initially and become
thickened and fleshy, later developing a dusty,
white coating of spores. Infected leaves fall
prematurely and new, healthy leaves may
appear later in the summer.
Chemical Control
(rate per 100 L water; or per
Cultural Management
unit area if indicated)
COPPER 53W: 400 g
Prune out diseased twigs
COPPER SPRAY 50: 600 g during the dormant season.
Apply before fall rains and
again when the majority of
leaves have fallen. Copper may
cause leaf spotting under cool,
cloudy conditions.
FLINT 50WG: 210-280g/ha
ZIRAM 85W: 8 kg/ha
Avoid planting susceptible species in beds known to be
infested. Remove all galls when moving stock. Disinfect all
tools and work areas with a strong bactericide when working
with gall-infected material. Inspect roots and do not plant
gall-infected material. See General Disease Management: Crown
Gall, Chapter 9.
Apply at leaf drop or in early
spring before bud break:
BRAVO 500: 5-7 L/ha
COPPER SPRAY 50: 200 g
COPPER 53W: 190 g
Repeat before bud break in
spring unless another dormant
spray has been used.
Apply by the end of January:
FERBAM 76 WDG: 175-350 g
Dormant:
LIME SULPHUR: 10 L
Verticillium Wilt (Verticillium spp.): See General Disease Management: Verticillium Wilt, Chapter 9.
Minimize wounding
especially during wet
weather. Prune as late as
possible in the dormant
season. It is important to
remove all cankered wood
from the vicinity of the
nursery or orchard.
Whitening of the bark to
prevent sunscald is also a
useful preventive measure.
Avoid excessive nitrogen or
irrigation in the growing
season.
Use virus-tested stock for
propagation of both sweet
and flowering cherries.
Refer to Little Cherry Control
Regulations, Chapter 2, for
restrictions on movement
and production of cherries
in the Little Cherry Control
Areas of BC.
Where practical, pick and
destroy infected leaves
before sporulation occurs in
early summer.
Fall sprays will also control
Coryneum blight.
Nursery Production Guide Pests of Specific Crops • 31