Pests of Specific Crops

Pest Description
CORYLUS - HAZELNUT
Diseases:
Bacterial Blight (Xanthomonas arboricola pv. corylina):
New buds and shoots are blighted and oneand
two-year-old twigs may have sunken
purple-brown cankers. Trees may be girdled
and killed at the base of the trunk (crown)
during the first 10 years. Tissue under the bark
of cankers and infected crowns is reddishbrown.
Leaves may have small (2-3 mm),
angular, water-soaked spots that turn reddishbrown.
Roots are seldom infected.
Eastern Filbert Blight (Anisogramma anomala):
Infected branches show up from July to
September when leaves turn brown but remain
on the branch. Oblong, raised bumps (fungal
fruiting bodies) in relatively straight rows
begin to form under the bark of infected
branches in June. By August the bumps are
white, football shaped structures that have
broken through the bark. These fungal
structures turn black as they mature in the fall.
COTONEASTER
Diseases:
Bacterial Blight (Pseudomonas syringae pv. syringae):
New growth wilts and turns black in the
spring. The disease may occur at any time in
propagation houses. It is common at the Coast.
Dark Berry (Phytophthora cactorum): Berries turn
brown to black and eventually shrivel up.
Fire Blight (Erwinia amylovora): Flowers and new
shoots wilt suddenly and turn brown. Dead
leaves hang downward on affected twigs. This
disease is rare at the Coast but common in the
Interior.
Scab (Venturia sp.): This fungus causes shedding of
blossoms, and dark, blotchy spots on leaves
and fruit. Diseased leaves can be curled and
distorted. New infections can occur whenever
there is a moderate to prolonged rainy period
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
COPPER SPRAY 50: 300-900 g
depending on tree size. Apply
before fall rains, at ¾ leaf fall and
before spring bud break.
Maximum 3 applications per
year.
BRAVO 500: 6.72 L/ha
COPPER SPRAY 50: 300-900 g.
Apply from bud swell to bud
break at 10-14 day intervals; up
to 3 applications per year. Use
low rate on small trees and high
rate for large trees.
FLINT 50WG: 140-280g/ha
QUADRIS: 90 mL. From bud
swell to bud break
(approximately mid-March to
mid-May), apply at 7-10 day
intervals prior to disease
development.
Cultural Management
See the Ministry’s Hazelnut
Pest Management Guide.
Protect trees from sunscald
during the first few years. The
bacterium infects through
wounds, so disinfect pruners
between cuts. Prune out
infected branches 60-90 cm
below lesions. ‘Barcelona’ is
highly susceptible; ‘Du Chilly’
is susceptible; ‘Daviana’ is
intermediate and ‘Hall’s
Giant’ is resistant.
If you see suspicious
symptoms, contact the
Ministry’s Plant Pathologist in
Abbotsford. The CFIA has
initiated the process to
deregulate the disease.
‘Daviana’, ‘Butler’ and ‘Ennis’
are highly susceptible;
‘Barcelona’ is moderately
susceptible; and ‘Willamette’
and ‘Hall’s Giant’ are
resistant. Ornamental
contorted hazelnuts are also
susceptible.
See General Disease Management: Bacterial Blight/Canker, Chapter 9.
Infection can be reduced by
mulching to prevent soil
water splashing and by
planting in sunny locations
with good air circulation.
See General Disease Management: Fire Blight, Chapter 9.
Copper sprays applied for fire
blight may also give some
control of scab.
Rake and burn, bury or compost
fallen leaves and fruit. A similar
fungus causes scab on other
Rosaceae. See under MALUS –
APPLE and CRABAPPLE.
12 • Pests of Specific Crops Nursery Production Guide