How to Manage Pests
UC Pest Management Guidelines
Scientific name: Synanthedon exitiosa
(Reviewed 10/14, updated 10/14)
In this Guideline:
DESCRIPTION OF THE PEST
Peachtree borer eggs are laid during the summer on the bark at the base of trees. Larvae overwinter in the tree trunk near the soil line. They feed in the crown area and burrow up into the tree. At maturity, a larva is about 1-inch long, and has a light-colored body and a dark head. In late spring, larvae pupate near the entrance of their burrows or in the soil. Adults emerge from May through September; they are steel blue to black clearwinged moths with a 1-inch wing span.
DAMAGE View photos of borer damage
Peachtree borers can girdle and kill young trees. Older trees can withstand the damage unless there are many larvae or the tree is attacked several years in a row.
Look for the presence of frass and gum at the bases of trees when monitoring orchards in spring. Also check trees in fall for signs of peachtree borer activity. At this time, you can kill larvae by carefully using a knife or wire to probe the trunk. Mark infested trees that you find, and return the following spring to apply insecticide by spraying the trunk from the scaffold to the soil line.
You can use pheromone traps to monitor adult emergence. They are useful for determining the presence of peachtree borers. The pheromone lure may be listed as peachtree borer or greater peachtree borer, but do not use lesser peachtree borer lures. Be sure to properly identify the moths that are trapped; other clearwing moths, the strawberry crown borer for example, may be attracted by the peachtree borer pheromone. For higher peachtree borer numbers, pheromone bucket traps work better than other pheromone traps.
Pheromone mating disruption has been successfully used in other states but is not currently registered in California.
Keep tree bases free of vegetation to help reduce problems with peachtree borer, especially in the Central Valley. Heat and dryness reduce the survival of eggs and larvae.
UC IPM Pest Management Guidelines: Apricot
Insects and Mites
W. W. Coates, UC Cooperative Extension, San Benito County
Acknowledgment for contributions to Insects and Mites:L. C. Hendricks, UC Cooperative Extension, Merced County