Pests of Specific Crops

Pest Description
Chemical Control
(rate per 100 L water; or per
unit area if indicated)
PRUNUS LAUROCERASUS - CHERRY LAUREL
Diseases:
Leaf Spots, Shot-hole - Bacterial (Pseudomonas
syringae pv. syringae), Fungal (Cercospora spp.
and other fungi): The bacterium, Pseudomonas
syringae, and several fungi can cause reddishbrown
leaf spots that may fall out giving the
leaf a shot-holed appearance. Identification of
the causal agent is often difficult, but may be
necessary for selection of the proper chemical
control. Fungal diseases are more common in
the Interior and bacterial blight at the Coast.
Insects:
Cherry Bark Tortrix (Enarmonia formosana): The
larvae live under the bark and show a
preference for scar tissue from graft unions.
Frass (excrement) and gum-like resin can be
observed at the entrance of the tunnels. The
larvae overwinter and pupate in the spring
inside the tunnels. Moths have dark brown
forewings with yellow-orange lines. They
emerge in May and periodically through the
summer.
Cherry Ermine Moth: See MALUS: Apple Ermine Moth.
Leafrollers: Larvae are green with black heads. They
feed on leaves and fruit, and drop on silk
threads when disturbed.
Peach Tree Borer (Synanthedon excitiosa): It affects
apricots, cherries, chokecherries, nectarines,
peaches, plums and prunes. Females lay eggs
near the soil line on tree trunks where, after
hatching, the larvae tunnel under the bark.
Larvae are cream colored with brown heads
and reach up to 30 mm long. Adults are clearwinged
moths around 25 mm long with yellow
banded abdomens. Can girdle and kill young
trees. Older trees are weakened and become
susceptible to other pests.
Pear Sawfly (Caliroa cerasi): Adult is a shiny black fly
with four wings. Black slug-like larvae
skeletonize leaves in summer.
Apply fungicide or bactericide
to protect new growth in
spring.
Fungal:
DACONIL 2787F: 250 mL
DACONIL Ultrex: 150 g
See General Disease Management:
Bacterial Blight / Canker, Chapter
9.
Because of the long flight
period of the moths and the
bark-boring habit of the larvae,
effective chemical controls have
not been developed.
Cultural Management
Avoid overhead irrigation
in the afternoon or evening.
Destroy fallen leaves. Very
susceptible varieties such as
‘Zabeliana’ cannot be
grown disease-free in
containers under sprinkler
irrigation. They can be more
successfully grown in the
field. They must not be
subjected to daily
sprinkling in the landscape
and they should not be
planted under any type of
cherry tree.
Older infested trees should
be cut down to reduce
breeding of this insect.
DIAZINON 50WSP or 50EC (cherries): 100 g or 100 mL
DIPEL WP: 2.25-3.35 kg/ha
DIPEL 2X DF: 1.125-1.675 kg/ha
DOKTOR DOOM: 60-480 mL/0.4 ha
IMIDAN 50-WP: 3.75 kg/ha
ORTHENE 75% SP: Mist blower = 1,312 g/1,000 L; Hydraulic
sprayer = 637 g/1,000 L
SEVIN T&O: 230-350 mL
Spray when bearing trees are in pink-bud stage.
DECIS 5 EC: 6.8 mL
ISOMATE-P PHEROMONE:
250 to 625 dispensers/ha for
peaches, nectarines and
apricots. One dispenser per
tree. Apply in the spring prior
to moth emergence, one
application can provide seasonlong
control.
MILLENIUM: 1 tray/9.4 L
THIONEX 50 W: 150 g
See General Insect and Mite
Management: Sawflies, Chapter
11.
Install a metal cone-shaped
collar around the base of
the tree before eggs are laid
to prevent larvae from
boring into the base of the
tree. Kill larvae in tunnels
by probing with a wire or
by opening the tunnels to
find and destroy them.
Apply when damage is first
noticed in spring and again
in July-August.
32 • Pests of Specific Crops Nursery Production Guide