The spongy moth, Lymantria dispar, is a highly destructive forest pest and one of the council’s top priority species. The moths eat the leaves and needles of conifers and hardwood trees alike, killing the trees and causing widespread ecological damage. They can spread rapidly because the females fly.
The spongy moth entered the United States in 1992 in a shipment of grain. A massive effort by federal and state agencies wiped out most of them. Today, Washington sees new introductions every year, with moths mostly brought to new areas by people.
The establishment of spongy moths likely would lead to quarantines on products from the infested areas, with significant economic impacts.
Every summer, the Washington Department of Agriculture catches spongy moths Western Washington. Positive detection sites are inspected for additional evidence of spongy moth presence such as egg masses, pupal cases, and cast skins before determining the need for an eradication effort. Thanks to the department’s ongoing surveillance work, no permanent populations of spongy moth have been found in Washington.