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WSDA to begin gypsy moth treatments

The agency will aerially treat about 640 acres in Cowlitz County with a naturally occurring soil bacteria beginning May 10.

May 7, 2021

3 Min Read
Gypsy moths pose a serious threat to Washington’s environment, with the caterpillars feeding on over 500 types of trees, plants and shrubs.USDA ARS

The Washington State Department of Agriculture (WSDA) plans to begin treatments to eradicate a gypsy moth introduction starting Monday, May 10, weather permitting. In total, WSDA will aerially treat about 640 acres with a naturally occurring soil bacteria, Btk (Bacillus thuringiensis var. kurstaki.)

WSDA plans to treat only one site this year – at Silver Lake. A low-flying airplane will apply Btk using GPS guidance to ensure on-target application. The site will be treated three times, with each application approximately 3 – 14 days apart. All treatments are weather dependent and the schedule is subject to change. WSDA expects to complete all applications by the end of May.

Because weather conditions heavily influence when treatments occur, WSDA advises people in or near the treatment areas to visit agr.wa.gov/gypsymoth to sign up for alerts via e-mail, text or robo call, which are issued the day before applications are scheduled to take place. Changes in scheduled treatments will also be shared through these notification systems. WSDA also mailed postcards to residents in and near the treatment areas advising them of the upcoming treatments. The public can also enter an address in a map on the agency website to determine whether their residence is within or near the treatment area.

According to the Washington State Department of Health (DOH), Btk poses very low risk to humans, pets, birds, fish and bees. Btk is found naturally in the environment and has an excellent safety record while also being effective for gypsy moth eradication. Although the risk to humans is low, as a precaution, DOH recommends that people minimize their exposure to the spray by remaining indoors with doors and windows closed during spraying and for 30 minutes afterward, let the spray dry before allowing children to play outside, wash with soap and water if you do have skin contact with the spray, and rinse your eyes with water if eye contact occurs.

Btk is sticky. Residents in the treatment areas may choose to cover cars parked outside and bring in toys, etc. to protect them from the spray. However, Btk can be cleaned off outdoor articles with soap and water.

A serious environmental threat

Gypsy moths pose a serious threat to Washington’s environment, with the caterpillars feeding on over 500 types of trees, plants and shrubs. The pest is permanently established in 20 states across the Northeast and Midwest, where it has defoliated millions of acres of forest and urban trees. In 2017, gypsy moth caterpillars defoliated one-third of the entire state of Massachusetts and in 2018, they lost about one-quarter of their hardwood trees, including three-quarters of their oak trees, in large part due to gypsy moth infestations.

If gypsy moth were to become established in Washington, it would threaten forest ecosystems, lead to quarantine restrictions on forest products and horticulture, and result in long-term increased homeowner pesticide use.

WSDA has been trapping for gypsy moths for over 40 years and has successfully prevented them from establishing in Washington by safely eradicating reproducing populations. Visit the agency’s gypsy moth web page at agr.wa.gov/gypsymoth to learn more or contact the WSDA Pest Program at [email protected] or 1-800-443-6684.

Source: Washington State Department of Agriculture, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset. 

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