New Jersey Audubon Stewardship staff were collecting vegetation data on a private property in Sussex County this summer. During the inventory, they noticed a forest health pest.
The spongy moth (Lymantria dispar dispar), formerly known as the gypsy moth, is a non-native invasive species that was introduced to North America in the late 1800s. The moths are dimorphous, which means the males and females differ in appearance. The females are primarily white in color and are flightless, whereas the males are smaller, brown moths which fly to the females to mate. The female moths lay egg masses in late summer, which are light brown, covered in fine hairs, and spongy in texture which gives the moths their name. They overwinter as eggs, and in spring the larvae (or caterpillars) emerge, climbing trees to feed on the leaves. When they occur in large numbers, the caterpillars can cause severe defoliation. While most trees can recover from this, subsequent years of repeated defoliation can weaken and sometimes kill trees.
In many cases, outbreaks are eventually managed by diseases which effect spongy moth caterpillars and reduce their populations. However, there are steps you can take to reduce the presence of spongy moths and protect the trees on your property. Egg masses are laid in late summer, so they are prevalent now.  If you notice these egg masses on your trees or other smooth surfaces around your property, you can remove the egg masses by scraping them into a bucket of soapy water and leaving them overnight which will destroy the eggs.
Photos by Danielle Bara, Stewardship Project Coordinator
