Roundheaded appletree borer
Saperda candida Fabr.
Adult (A) has a hard, elongated body, with white and brown longitudinal stripes and long antennae. The larva is a fleshy, cream-colored legless grub with a dark brown head, blackish mandibles. The first thoracic segment broader than the rest of the body (B).
Most fruit-growing states and provinces in eastern North America.
Attack apples mainly, but most deciduous tree fruits are susceptible. The larvae dig tunnels, most often at the base of the tree trunk. The roundheaded borer leaves accumulations of reddish frass at the entrance of galleries. Infested trees have a sickly appearance, producing sparse, pale-colored foliage (C). Continued yearly attacks can kill the tree or weaken it so that it is broken off by the wind. Young trees that have been girdled will often bloom profusely and set a heavy crop of fruit and then die in the process of bringing it to maturity.
This pest can easily become a serious problem in neglected or backyard apple trees. Eliminate alternative hosts (rosaceous trees) growing in close proximity. Protect trees against egg laying at the base of trunks (mosquito netting), and eliminate weeds at base of tree trunks. An insecticide can be applied to the trunk against egg-laying adults in early to midsummer.
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.