European Gypsy Moth

Survey in Progress

The U.S. Department of Agriculture (USDA) and your 

State government need your help to track and prevent the 

spread of an invasive pest called the European gypsy moth 

(Lymantria dispar). The traps that we have placed on trees 

in your neighborhood are part of an important survey of the 

moth. Please do not move the traps. 

The gypsy moth is a serious threat to forest, shade, and 

ornamental trees. Feeding on the leaves of at least 300 

host species, gypsy moth caterpillars defoliate and weaken 

the trees that make up our national forests and community 

landscapes. In heavy infestations, the caterpillars can 

completely strip the leaves from host trees over wide 

geographic areas. If repeated, this defoliation will cause the 

trees to weaken and eventually die. 

To fight the gypsy moth, two USDA agencies—the Animal 

and Plant Health Inspection Service (APHIS) and the Forest 

Service—partner with State departments of agriculture. 

Together, we carry out gypsy moth survey, regulatory, 

eradication, and outreach efforts. Our goal in surveying is to 

find new gypsy moth infestations early, before populations 

can establish, grow, and spread. Your cooperation in these 

efforts will help to stop the spread of gypsy moth. 

Gypsy moth caterpillar Delta trap

Milk carton trap

Gypsy moth adult male Gypsy moth egg mass

USDA is an equal opportunity provider, employer and lender.

Animal and Plant Health Inspection Service

State Departments of Agriculture

Program Aid No. 2154 • Issued October 2014 • Reprinted July 2017

This publication supersedes Program Aid No. 1570, “Keeping Track of the Gypsy Moth,” 

which was published in November 1996.

United States Department of Agriculture
Q. Is gypsy moth a serious pest?

A. Yes. The gypsy moth was accidently introduced into the 

United States in 1869 and continues to be one of the most 

destructive tree pests in our country. Native to Europe, 

the gypsy moth has spread throughout the northeastern 

United States and into areas of the Midwest, infesting and 

defoliating millions of acres of trees. 

Q. How does the gypsy moth spread?

A. Although female gypsy moths can’t fly, the insect can 

move long distances as a hitchhiker. It often spreads to 

new locations when people moving from an infested area 

unintentionally transport gypsy moth egg masses and other life 

stages on outdoor household items, such as vehicles, firewood, 

nursery stock, and lawn furniture. This human-assisted 

movement creates “spot” infestations and advances the pest’s 

spread into areas that were previously gypsy moth-free.

Q. What do the gypsy moth traps look like, and how do 

they work?

A. The traps are green, orange, or brown and are made of 

plastic-coated cardboard. The smaller “delta” trap looks like 

a pup tent with openings on each end; the taller and larger 

trap looks like a milk carton and is named accordingly. 

Both traps are baited with a lure that attracts the male moth but 

has no effect on people, animals, or other insects. Once the 

male moth enters a trap, it is either caught in the sticky lining 

(delta trap) or killed by a small, insecticidal strip (milk carton).

Q. Are the gypsy moth traps safe?

A. The traps pose no risk to people, pets, or wildlife. 

Q. How can I support the gypsy moth survey?

A. Talk to your family and friends about the survey and 

why it’s important. The gypsy moth traps are in host 

trees throughout the summer—please do not move them. 

Pinpointing gypsy moth locations is difficult if traps are 

missing or disturbed. If you see a trap on the ground, locate 

the handwritten identification number on the outside of the 

trap, and call the phone number listed below to report it.

Q. What can I do to help keep gypsy moth from 

spreading?

A. Know the quarantines and requirements in your 

area, especially if you’re relocating. Find out more at 

YourMoveGypsyMothFree.com. Also, become familiar with 

the signs of a gypsy moth infestation and report any findings 

at www.HungryPests.com.

Q. Where can I get more information?

A. If you have questions or wish to report a fallen trap, 

call the phone number listed below, or contact your State 

agriculture department (www.nationalplantboard.org/member) 

or nearest USDA office (www.aphis.usda.gov/planthealth/sphd).