BRONZE BIRCH BORERS
The Bronze birch borer is another flat-headed borer like the ash borer that attacks ash trees and the 2-lined chestnut borer that attacks other hardwoods, especially oaks in Michigan.
We also have the honey locust borer, another flat headed borer and similar borers that attack elms, lindens, and others.
These borers, unlike the ash borer, are native borers, so their hosts have evolved some resistance to attack. However, trees that are stressed by drought, root damage, or other insect or fungal problems can be susceptible.
In the instance of birch trees, native trees have some resistance, however, landscaping birch trees are often from European stock or Asian stock and are very susceptible to attack by the birch borers.
PREVENTION AND/OR TREATMENT
The birch borers can be prevented with conscientious use of annual soil drench or injection with imidacloprid.
An alternative for larger trees is trunk injection with emamectin, the chemical used for ash borers.