Pest description and crop damage Peachtree borer is native to North America and common in the Northwest. The adult is a metallic blue-black, clear-wing moth. The male moth may have bands of light yellow on the abdomen, which makes it resemble a wasp. The female has an orange band around the abdomen. Full-grown larvae are 1 inch long and whitish with a brown head. The larvae burrow into the bark of the crown and feed on the cambium. Feeding is restricted to an area a few inches above and below the soil line. Young trees can be completely girdled and killed. Older trees rarely are girdled, but the feeding reduces vigor and makes them vulnerable to other pests and diseases. Infested trees bleed frass-infested gum during the growing season.
Biology and life history The borer overwinters as a larva on or under the tree bark, usually below ground. As temperatures rise above 50°F in the spring, the larva resumes feeding on the tissues under the bark. At maturity in May and June, the larva pupates. Adult moths emerge beginning in June and continue through September. Eggs are laid quickly after mating. Young larvae hatch after 8 to 10 days and bore immediately into the base of the tree.
Scouting and thresholds Pheromone traps are available for this peachtree borer. This insect can do substantial damage if not controlled: one larva can kill a small tree. Entry holes and borer damage greatly affect marketability; action thresholds are very low. Prevention is key.
Management- cultural control
Rogue and destroy infested plants.
Mating Disruption Pheromone mating disruption (Isomate P) at 100-250 dispensers/a. Dispensers must be placed in trees before first moth flight. Flight is usually from late June through September. If mating disruption is used, monitor blocks with traps baited with peachtree borer lures at 1 trap/2.5 a. If one or more moths are caught, a conventional insecticide application may be required.
Apply in June and repeat at 3- to 4-week intervals throughout summer.
For more information
Johnson, W.T. and H.H. Lyon (1991), Insects That Feed on Trees and Shrubs, 2nd ed., Cornell University Press (p. 258-261).
PNW Nursery IPM: Peach Tree Borer Mating Disruption (http://oregonstate.edu/dept/nurspest/peach_tree_borer.htm)