News Releases

OLYMPIA – The Washington State Department of Agriculture (WSDA) is proposing to treat one area in Cowlitz County next spring to eradicate an introduction of Asian gypsy moth, a non-native, invasive pest that can decimate the environment. The proposal calls for treating a total of about 639 acres near Silver Lake.

WSDA’s proposal involves aerial applications of a soil bacteria called Bacillus thuringiensis var. kurstaki, or Btk, which is an insecticide approved for use in organic agriculture. It has an excellent safety record around people, plants, pets, fish, birds and bees and has been used globally for decades as a safe and effective treatment for combatting gypsy moth. Treatments occur as gypsy moth caterpillars emerge in the spring and begin to feed on vegetation.

Gypsy moth caterpillars feed on hundreds of trees and shrubs, often killing these plants in neighborhoods, parks, and forests. The pest also destroys wildlife habitat and some people are allergic to the caterpillars. An infestation can also trigger costly quarantines for timber, Christmas trees, and other forest and nursery products.

This summer and fall, WSDA trapped nine gypsy moths – eight European and one Asian gypsy moth. More destructive than its cousin, the Asian gypsy moth can feed on a wider variety of trees and the females can fly, so populations can spread more quickly and do more damage to the environment.

Next steps for WSDA include preparing two environmental reviews; consulting with local, state and federal agencies; and public outreach that includes a virtual informational open house. Residents in or near the proposed treatment area will also receive postcards notifying them of the proposal.

Visit agr.wa.gov/gypsymoth to learn more and find maps of the proposed treatment area. Gypsy moths were initially detected in Washington in 1974, but no permanent populations have been established here due to WSDA’s successful trapping and treatment program.