MONTPELIER, Vt. (WFFF) — Gypsy moth caterpillars are defoliating many of Vermont’s trees. According to the Vermont Agency of Agriculture, Food & Markets, the invasive pests are making a comeback.

There hasn’t been a large outbreak of gypsy moth caterpillars in the Green Mountain State since 1991. However, forestry experts say dry weather within the last few years has limited the prevalence of a specific fungus that kills the caterpillars, leading their population to increase.

Gypsy moth caterpillars’ food of choice is oak leaves, but they can eat many types of leaves, including maple and pine. Defoliation is a significant stress factor in plant health.