Pests of Specific Crops

Pest Description
SALIX - WILLOW
Diseases:
Blight (Marssonina salicicola, Septoria spp. and other
fungi): These fungi overwinter as twig cankers.
During wet spring weather, new leaves and
shoots become infected. Under severe
conditions, defoliation and extensive twig
death occurs.
Insects:
Alder Flea Beetle (Altica ambiens ulni): The beetle is 6
mm long, metallic green to blue with yellow
legs. The adult and larval stages skeletonize
leaves, but seldom cause serious injury.
Aphids: A small to medium-sized, light green or
yellow aphid sucks sap from leaves. A large,
black aphid feeds on the bark of twigs. Large
numbers produce much honeydew and attract
wasps.
Poplar and Willow Borer (Cryptorhynchus lapathi):
The adult beetle is 6 mm long, dark brown,
mottled, with light brown, grey, and pink
scales. Larvae feed in soft tissue of inner bark
and sapwood, especially at the base of the tree,
which they kill.
Satin Moth (Leucoma salicis): The larvae are
defoliators of cottonwood, poplar and willow,
and occasionally attack oak and aspen.
SKIMMIA
Diseases:
Black Root Rot (Thielaviopsis basicola): T. basicola is a
soil-inhabiting fungus that causes root rot on a
broad range of ornamental plants. The disease
is favoured by wet and warm (12-18 o C) soils.
The symptoms include yellowing of foliage,
branch dieback, and blackened areas on roots.
SORBUS - MOUNTAIN ASH
Diseases:
Apple Scab (Venturia inaequalis): This fungus causes
scab (black spots) on leaves and fruit. Leaves
are curled and distorted. New infections occur
whenever there is a moderate to prolonged
rainy period. The same fungus causes apple
scab.
Fire Blight (Erwinia amylovora): New shoots wilt
suddenly in late spring and turn black or
brown. Dead leaves hang downward on
infected twigs. It is not considered to be a
problem in Coastal areas.
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
No fungicides are registered
for control of these diseases
on willow.
Cultural Management
In nurseries, prune and burn
diseased twigs at least twice
per year. See under
POPULUS.
See General Insect and Mite Management: Aphids, Chapter 11.
DURSBAN WSP: 44.8 g See under POPULUS and in
PRO DURSBAN TURF: 50 mL General Insect and Mite
Management: Bark Beetles and
Wood Borers, Chapter 11.
See under POPULUS and in General Insect and Mite
Management: Caterpillars and Moths, Chapter 11.
SENATOR 70WP: 65-85 g
Rake and destroy fallen
leaves. Control scab on apples
if grown nearby (see under
MALUS).
See General Disease Management: Fire Blight, Chapter 9.
Nursery Production Guide Pests of Specific Crops • 39