The peachtree borer, Synanthedon exitiosa, is a pest primarily of peach and nectarine trees, but it also attacks apricot, cherry, and plum trees.
The peachtree borer larva is white with a brown head, and is 1.5 inches long at maturity. When flying, adults resemble wasps and often are mistaken for them. The female moth is dark blue with a broad orange band around the body; the forewings are darker than the back wings, which are clear. The male is smaller and has three to four narrow, yellowish bands across his body; both pairs of wings are clear.
Borers overwinter in the larval stage in a range of sizes. Larvae become active and resume feeding in April; larger larvae complete their feeding during June and July. Most adults emerge and lay eggs during July and August.
The female moth is capable of laying approximately 500 eggs. They are laid on tree trunks, in cracks or under bark scales, and in soil near the tree trunk. Eggs hatch in 10 days, and young larvae feed on tree bark, working their way into the trunk as they become larger. They are attracted to previously infested or injured trees. Only one generation is hatched each year.
One of the first signs of peachtree borer attack is a mass of gum exuding from the trunk base anywhere from 3 inches below to 1 foot above the soil surface. This gum mass contains bits of wood chips, sawdust, and frass produced by the feeding larvae. Burrowing larvae weaken the tree, resulting in lower fruit production or, if borers are numerous, in the death of the tree. Neglected trees, or those suffering from drought or winter injury, are most likely to be infested by these borers.
Several methods can be used to control this pest after infestations have been noted. Individual larvae can be killed by stabbing them with a length of wire inserted into their burrows. A different control method involves spraying a pesticide containing one of the pyrethroid insecticides such as esfenvalerate or permethrin onto the affected area of the trunk.