Notes on Stone Fruit Insects &
Mites
Peachtree borers
Identification
Peachtree borer (PTB) larvae damage stone fruit trees by boring into
trunks and branches, and feeding on the growing tissue (cambium) and inner
bark. The PTB confines its activities to the trunk area; feeding can completely
girdle and kill young trees. Larvae of the lesser peachtree borer (LPTB)
are associated with previously damaged or diseased plant tissues, which
include cankers, pruning wounds and winter or insect-injured areas.
Period of activity
Both species overwinter as larvae. The PTB completes its development
in the summer, with adult moths emerging from July through September.
Emergence pattern of the LPTB is prolonged and less synchronous, and occurs
from late May through September. Peaks occur from June through July.
Monitoring and thresholds
Pheromone traps are used to monitor the emergence of male moths throughout
the season. In areas with high peachtree borer pressure like southwestern
Ontario, controls are timed to coincide with peak moth activity. Monitor
trees for the presence and abundance of peachtree borers. Examine trees
for the presence of sawdust-like frass and exuded gum. The pupal cases
of emerged moths can often be found near the surface of damaged tissues.
Management notes
Lesser peachtree borer and peachtree borer can be serious problems in
apricot blocks. Redirect a nozzle when you spray insecticides for plum
curculio and preharvest cover sprays. This provides spray coverage of
the trunks and lower scaffolds.
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