OLYMPIA, Wash. – The Washington State Department of Agriculture’s (WSDA) spongy moth* (Lymantria dispar) trappers had a busy season this year, trapping 103 spongy moths. Thirty moths were caught statewide in 2022 and only six in 2021.

The spongy moths were caught as part of the WSDA Pest Program’s regular summer moth survey program, during which more than 20,000 traps were placed around the state this year. Of the moths trapped, 81 were in Thurston County, with 77 trapped near Steamboat Island Road, making that the most moths trapped in one area in more than 30 years. Other counties with spongy moth catches include Pierce, Skagit, King, San Juan and Snohomish.

“We had a surprising number of catches this year,” Susan Brush, Acting Invasive Moth Projects Coordinator, said. “Our next step is to look for egg masses in the areas with the highest concentration of catches. Once we have that information, we’ll have the data necessary to start planning our response to this introduction.”

WSDA has monitored and successfully prevented spongy moth from establishing in the state since 1974. Each year, the state has new introductions of the invasive pest from people moving from the Eastern U.S. where 20 states are permanently infested with the moth or, more rarely, through the ports.

Spongy moth is an extremely destructive pest that threatens entire forests, parks and neighborhood trees and shrubs. The moths can defoliate acres of trees during outbreaks, which can result in the death of millions of trees and the destruction of native habitat for countless species. During an outbreak in eastern states in 2016, the damage was so extensive it could be seen on NASA satellites.

Visit agr.wa.gov/moths for more information about spongy moth and WSDA’s trapping and eradication programs.

* Spongy moth was formerly known as gypsy moth. The common name changed in 2022.

— WSDA