Dogwood Borer

What it looks like

Adult dogwood borers are clearwing moths that look like small wasps, with a dark blue-black body, a yellow band, and mostly clear wings. The caterpillars are cream-colored with a brown head.

The caterpillars live under the bark, feeding in the living wood, and spend the winter there.

Damage

The caterpillars tunnel under the bark of dogwoods and apple trees, especially in burr knots (the rough, knobby growths on apple rootstocks) and in injured bark. Repeated attacks over several years can girdle and kill a tree.

How nematodes help

The beneficial nematodes in BioLogic's products enter the caterpillars' tunnels and kill them under the bark. A Cornell research project sprayed BioLogic's own Ecomask on the lower trunks of apple trees and got borer control comparable to growers' insecticide programs. In that study, spraying on a cool day in September worked better than spraying in hot July weather.

How to apply

Treat with Scanmask from March to July, or in September. Ecomask also works. Apply on a cool, moist evening.

Spray the lower trunk and the base of the tree, including rough bark and burr knots on the rootstock.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.