Integrated Pest Management

Damage

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.

Management

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.