Pests of Specific Crops

Pest Description
Douglas Fir Needle Midge (Contarinia sp.): The adult
is a small midge that emerges when buds are
breaking. The fly lives for a few days; just
enough time to mate and lay eggs. They
deposit eggs in groups on expanding buds and
new needles. The eggs hatch in a few days. The
larvae penetrate and mine needles, and drop to
the ground in the fall to overwinter. Even light
infestations lower market value and
appearance of Christmas trees. Moderate or
heavy infestations cause serious defoliation.
Infested needles become yellowed and angle
sharply.
Silverspotted Tiger Moth (Douglas Fir Webworm -
Halisidota argentata): Newly-hatched larvae are
greenish-brown, fuzzy and about 6 mm long.
Later stages are up to 37 mm long, thickly
haired and tufted with reddish-brown, yellow
and black hairs. Larvae spin a tent or web
around a branch and feed in or around the tent.
PYRACANTHA - FIRETHORN
Diseases:
Fire Blight (Erwinia amylovora): New shoots wilt
suddenly in spring, turning black/brown. The
dead leaves hang down on infected twigs. It is
uncommon in Coastal areas, but can occur
during summer propagation in polyhouses.
Scab (Venturia pyracanthae): Black scabs or blotches
appear on leaves and berries.
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
DIPEL WP: 62.5 g
Apply when larvae first appear
in March and tent is still small.
Repeat spray in two weeks if
necessary.
Cultural Management
Christmas tree growers
should use emergence
cages placed on the
ground to determine
midge emergence.
Treatments should be
applied when the buds are
stretching.
Prune out and destroy
tents when seen in fall or
spring.
See General Disease Management: Fire Blight, Chapter 9 and
COTONEASTER: Fire Blight.
BANNER MAXX: 14 mL
DACONIL 2787F: 250 mL or DACONIL Ultrex: 150 g
Spray when blossoms open and at 10-day intervals at least
twice more during early part of growing season.
Destroy all fallen leaves if practical. Appendix D contains a
list of resistant varieties.
PYRUS – PEAR (For Commercial Orchards - See BCMA Tree Fruit Production Guide)
Diseases:
Anthracnose Canker (Cryptosporiopsis curvispora): See under MALUS.
European Canker (Nectria galligena): See under MALUS.
Fire Blight (Erwinia amylovora): New shoots wilt
suddenly in spring, turning black/brown. The
dead leaves hang downward on affected twigs.
This bacterial disease is not considered to be a
problem in Coastal areas. In the Interior, it can
spread quickly at temperatures above 18°C in
wet weather, especially following hail damage.
Symptoms can be confused with Pseudomonas
blossom blast, which is more common on the
Coast and occurs earlier in the spring.
See General Disease
Management: Fire Blight,
Chapter 9.
Prune out diseased branches
at least 15 cm below the
affected area in dormant
season, or at least 30 cm
below the affected area in the
early growing season. ‘Bosc’
is highly susceptible and
whole branches may need to
be removed.
34 • Pests of Specific Crops Nursery Production Guide