Pests of Specific Crops

Pest Description
Insects:
Mealybugs: These scale-like insects are covered in
white, powdery wax. They feed on plant sap
and produce honeydew, which attracts ants
and leads to the growth of sooty mold.
Affected plants appear unthrifty and yellow.
Root Weevils: Both black vine and strawberry root
weevils attack camellia. The adults feed on
leaves; larvae on roots and the base of stems.
CANNA LILY
Diseases:
Canna Yellow Mottle Virus (Badnavirus): It was
detected in the Province in 2007. The
symptoms include yellowing and mottling of
leaf veins. It is reported to only infect Canna
lilies. It is spread by propagating from infected
stock plants. Insects have not been shown to
transmit this virus. Canna Mosaic Virus is also
known to infect cannas in North America.
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
Cultural Management
See General Insect and Mite Management: Mealybugs, Chapter 11.
See General Insect and Mite Management: Root Weevils, Chapter 11.
Remove and destroy infected
plants. It is important to use
virus free stock for production.
CEDRUS - ATLAS CEDAR, DEODARCEDAR, CEDAR of LEBANON
Diseases:
Tipblight (environmental Injury plus Sirococcus and
Sclerophoma spp. fungi): Twig tips dieback in
early spring, often forming a “hook”. Damage
can be extensive in years with warm winters
and occasional frosts, and very wet springs.
Both fungi have been found associated with the
disease in the Pacific Northwest.
CEANOTHUS
Diseases:
COPPER SPRAY 50: 400 g
Apply when new growth starts
in the spring and repeat 3-4
times at 10 day intervals.
Prune out infected twigs.
Protect small trees from frost
damage, if possible. The
disease is much less severe in
warm, dry springs.
Basal Rot of Stem Cuttings (Pythium/Phytophthora spp. and other fungi): See General Disease Management: Damping Off
and Stem Rot of Cuttings, Chapter 9.
CHAMAECYPARIS - FALSE CYPRESS, YELLOW CEDAR, PORT-ORFORD
CEDAR, LAWSON’S CYPRESS
Diseases:
Cypress Root Rot (Phytophthora lateralis primarily;
also Phytophthora cinnamomi and other spp.):
Roots of Lawson’s cypress become infected by
Phytophthora during periods of high soil
moisture or flooding. Infection moves into
larger roots and finally into the base of the tree,
causing a dark discolouration of the sapwood.
Foliage begins to lose colour, turning
completely brown within a few months. Large,
healthy trees often die completely in one
growing season once infection sets in.
There is no effective fungicide
treatment.
Use Lawson’s cypress that is
grafted onto a resistant
rootstock. Chamaecyparis
nootkatensis, C. pisifera and C.
thyoides are resistant, but the
graft union may not be longlived.
In the landscape, do not plant
Lawson’s cypress in areas
subject to flooding. Replace
dead trees with resistant
species, such as Thuja plicata.
Nursery Production Guide Pests of Specific Crops • 9