Winter moth caterpillars

If you've noticed an onslaught of little green caterpillars devouring the leaves on your trees, you are not alone - winter moth caterpillar season has kicked into high gear. We are receiving many reports from our report-a-pest form of this pest attacking trees, particularly in the eastern and southeastern part of the state. Many of you seeing this damage now will remember the moth in its adult form, as it is one of few moths in flight during the winter months.

While there are a variety of treatments to protect trees from winter moth and other defoliating caterpillars, one of the most promising management techniques is the effort to develop a biological control for this pest. Biologists at UMass Amherst have been working on just such a program, but it will take several years for the biocontrol to establish, so expect winter moths to continue to be a problem. More information about winter moth is available on our fact sheet.