State University Extension - Wapello County Peach tree borer is the most serious insect pest of peach trees.
Borers pass the winter as partially grown larvae underneath the bark.
Adult moths, which look like wasps, emerge from July until fall, and eggs are laid on the trunks of trees or in the soil a few inches from the trunk. The larvae feed in the outer layers of bark, penetrating deeper into the bark as they become larger. Because egg-laying lasts several months, a great variation in size of the larvae will be found in the fall. Infested trees will be killed by the extensive burrowing of larvae in the trunk. There is one generation each year in Iowa.