​A new common name for Lymantria dispar, spongy moth, replaced the prior name of this insect, gypsy moth, in 2022. Thank you for your patience and understanding as we transition through the name change process. For more information, visit the Entomological Society of America website.

Welcome to the UW-Madison Division of Extension Spongy Moth (Lymantria dispar) website.  This insect was formerly known as the “gypsy moth”, but the common name was changed in early 2022 to the spongy moth.

Each year, spongy moth (Lymantria dispar) caterpillars defoliate thousands of acres of hardwood forests, yard trees and other urban trees throughout the northeastern United States, including Wisconsin. This site offers tips on how to limit damage to your trees and describes available assistance programs.

The posts below provide management options for homeowners on a month-by-month basis.  Additional information about spongy moth, including identification, biology, history, and management can be found on the left hand side of the page.  Links to additional websites and publications are also provided.

For an outlook of the 2023 growing season, and discussion of the biology and management of spongy moth, check out the recently recorded webinar above.