Gypsy Moths in Fairfax County

The gypsy moth, Lymantria dispar, continues to be a serious insect threat to trees and shrubs in the United States. It is originally from the temperate regions of Europe, Asia and North Africa. In 1869, the gypsy moth became established in North America after escaping from a Massachusetts lab.

The caterpillar feeds on leaves of forest, shade, ornamental, fruit trees and shrubs. Gypsy moth caterpillars can defoliate a tree by eating 60 to 100 percent of the leaves. Hardwood trees such as oak and hickory may be killed by two or more defoliations, but a single defoliation may kill some evergreens. Some of the gypsy moth's favorite host trees are oak, hickory, beech, birch, willow and spruce.

Watch the Gypsy Moth Video

What do I look for?

Gypsy Moth Caterpillar

Gypsy Moth Caterpillar
Gypsy Moth Egg Mass

Gypsy Moth Egg Mass
Adult Gypsy Moth

Adult Gypsy Moths

Don't be fooled by these gypsy moth look a-likes

Gypsy Moth Suppression Program

Gypsy Moth Defoliation

Gypsy Moth Defoliation

Fairfax County Urban Foresters monitor for gypsy moths every summer and fall by counting gypsy moth egg masses throughout the county. This helps determine where active infestations are occurring. If serious infestations are found, the Forest Pest Branch develops a caterpillar suppression program. Homeowners and residents residing in or near the proposed treatment blocks are notified by mail in advance of the upcoming voluntary spray program. The material used for the suppression program is Bacillus thuringiensis kurstaki, a pesticide registered with the U.S. Environmental Protection Agency for use in forested residential areas.

What can you do?

Female Gypsy Moths Laying Egg Masses

Female Gypsy Moths laying egg masses

You can help detect gypsy moth infestations by keeping an eye out for the caterpillars in the spring and searching your property for egg masses later in the year. The female moths will lay their eggs starting in mid-July. The egg masses are tan colored and can be seen on the trunks and upper branches of trees or in sheltered areas, such as under the eaves of houses or in wood piles.

Gypsy moth management for homeowners

Scrape and Destroy

Scraping egg masses into a container of soapy water or bleach solution is an easy way to kill unwanted gypsy moths.

Report egg masses in your neighborhood

The Forest Pest Branch needs help finding the next big infestation of gypsy moths.

To report gypsy moth egg masses in your neighborhood

How to Find Gypsy Moth Egg Masses - Slideshare presentation

Gypsy Moth Slides

Community Gypsy Moth Management from Fairfax County

For more information, visit the national gypsy moth website or contact the Forest Pest Branch at 703-324-5304, TTY 711, or by e-mail if you find gypsy moth caterpillars on your property.

Photo credits:
Louis-Michel Nageleisen, Département de la Santé des Forêts,
Connecticut Agricultural Experiment Station Archive, Connecticut Agricultural Experiment Station,
Steven Katovich, USDA Forest Service,
USDA Forest Service - Region 8 - Southern Archive, USDA Forest Service,
Louis-Michel Nageleisen, Département de la Santé des Forêts,

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