Bronze Birch Borer

Bronze Birch Borer is a common insect that attacks most species of birch trees.

In late May/early June, the adult birch borer emerges, creating a distinct D-shaped holes in the bark.  After mating, females find crevices and scars to lay their eggs in the trunks and branches.  It's the larvae that burrows into the bark, typically living in the cambium of the birch trees.  They over-winter in the pupae form under the bark.

Bronze Birch Borers tend to attack trees stressed, often due to their environment.  Birch trees prefer shady, cool, moist area and are, therefore, unsuitable to many landscapes.  There are a few options for control of the Bronze Birch Borer:

1. Choose a less-susceptible species when planting a birch (i.e. River Birch or Gray Birch).

2. Provide you tree with the proper environment (shaded, somewhat moist areas, preferable on the north or east sides of the building.)

3. Use preventative applications to prevent the adults from laying their eggs.  The first should be done in late May, and the second about 3-4 weeks later.

for more info check out the Purdue Entomology Page - (.pdf)