Lymantria dispar - (Formerly called Gypsy Moth)

The Lymantria dispar is an invasive insect from Europe. Lymantria dispars generally feed in hardwood trees and cause severe defoliation that can lead to growth loss and dieback as well as make affected trees more susceptible to other stressors. Healthy hardwoods can survive several consecutive growing seasons of defoliation by Lymantria dispar before the pest causes significant impacts. Softwoods, which are defoliated after hardwoods have been stripped, can succumb to Lymantria dispar feeding in a single season.

Lymantria dispar larvae disperse by ballooning—they hang from a silk thread and can be carried by the wind up to a mile away. The larvae and egg masses can also be moved long distances on cars, recreational vehicles and equipment, firewood and personal belongings.

All of Maine is under quarantine for this pest. Find more info at USDA-APHIS.

In Maine, please report sightings of large numbers of this pest to the Maine Forest Service.

Lymantria dispar male
Male Lymantria dispar.

Lymantria dispar female eggs
Adult female depositing eggs.

Lymantria dispar female larva
Female Lymantria dispar larva.

Lymantria dispar hatching egg mass
Lymantria dispar caterpillars hatching from egg mass.

Numerous female Lymantria dispars laying eggs during a peak year for their population. Each egg mass will contain upwards to 800 eggs. (Charlie Burnham)
Lymantria dispar females and egg masses

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[Photos: Maine Forest Service, except last photo which is from Tawny Simisky, UMass Amherst]