Any time now, depending on nature’s whims, many of our trees will be hosting the tents of the native Eastern Tent Caterpillar. This handsome black caterpillar with white, yellow and blue markings is not related to gypsy moth caterpillars, with which they are sometimes confused. Last fall the female, a small, brown moth, laid her eggs on the branches where they overwintered as a firm brown mass.
The trees and the caterpillars have coexisted for centuries and both survive so for a mature tree it’s not a panic situation. New leaves will grow back after the caterpillars leave in late spring but defoliation of a small tree for several years could weaken it.
If you need exercise, prune or simply pull the nests out of the tree. Do this on a cloudy day or in the morning when most of the caterpillars are still in the nest.
Do not use a torch to burn the nests! This can do more harm to the tree, the torch bearer, and the surrounding property than the caterpillars will.
In the fall we’ll be seeing similar nests located at the end of the branches, not in branch crotches. These are the offspring off the Fall Webworm, a smaller, darker, and hairier nonnative. Again, because by this time the tree will already have completed its growth, the damage is more cosmetic than systemic. Not to worry.
Article written by Glenn Palmer, Extension Master Gardener Volunteer.