Pests of Specific Crops

Pest Description
Volutella Leaf and Stem Blight (Pseudonectria
rousseliana): Causes branch dieback and leaves
on affected branches to yellow and then turn
straw-tan in color. Diagnostic pink fungal
spore-producing structures develop on the
underside of affected leaves.
Insects:
Boxwood Leafminer (Monarthropalpus buxi):
Leafminers overwinter in the larval stage in the
leaves. In April they pupate in an orangecoloured
casing and emerge as a gnat-like fly
when Weigela begins to bloom. Eggs are laid in
the current year’s foliage. Damage is from the
larvae that hatch and feed within the leaves.
Boxwood Psyllid (Psylla buxi): Eggs, orange in colour,
overwinter between bud scales. Nymphs
emerge when the buds open. Terminal leaves
become cupped and protect the feeding insects.
Adults, greenish jumping “plant lice”, appear
in late spring.
CALLUNA - HEATHER
Diseases:
Root Rot (Phytophthora spp.): Infection first occurs in
fibrous roots, then spreads to the entire root
system and crown. Individual branches
dieback or yellow, followed by plant death.
CAMELLIA
Diseases:
Botrytis Grey Mould (Botrytis cinerea): Flowers, buds,
leaves and petioles brown and drop under high
humidity. Dead plant parts are covered with a
grey to brown, fuzzy mould.
Bud Drop/Brown Petals (Environmental): Flower
bud drop may occur if plants are located in
sites exposed to cold, dry winds or summer
heat. Bud drop can also be caused by low
winter temperatures, over-watering or drought
stress. Many older varieties are not winter
hardy in BC and regularly drop flower buds.
Bud drop will also occur if more buds develop
than the plant can support. Brown petals result
from spring frost damage to flower buds.
Flower and Petal Blight (Ciborinia camellias
(Sclerotinia camelleae)): Only flowers are
infected. Small brown spots on petals later
enlarge until the whole flower browns. Hard,
brown to black fungal bodies (sclerotia)
develop on the base of old infected flowers.
These can survive in soil for several years.
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
Apply an insecticide as soon as
growth starts in the spring. See
General Insect and Mite
Management: Leafminer / Needle
Miners, Chapter 11.
SEVIN T&O: 230-350 mL; spray
when new growth begins, or
when the insect or damage is
first seen.
Cultural Management
Prune and dispose of dead
branches and leaves in the
crown. Maintain good air
circulation to promote rapid
drying of foliage.
Gather and dispose of fallen
leaves to reduce the number of
leafminers.
For bed and container-grown plants, see General Disease
Management: Root Rot Caused by Phytophthora and Pythium, Chapter
9.
For cutting propagation, see Damping Off and Basal Rot of Cuttings,
Chapter 9.
See General Disease Management: Botrytis Blight and Storage Moulds,
Chapter 9.
CAPTAN 50-WP: 200 g
CAPTAN 80-WP: 125 g
MAESTRO 80DF: 125 g
Plant in sheltered areas in welldrained
soils that have good
organic matter content. To
avoid frost damage, choose
sites that do not receive early
morning sun. Select hardy
varieties. Water during hot, dry
weather.
Remove and destroy infected
flowers. Rake and burn old
leaves and infected flowers. Do
not compost. Remove surface
soil beneath heavily infected
plants.
8 • Pests of Specific Crops Nursery Production Guide