The Washington State Department of Agriculture will soon begin aerial spraying in a section of Pierce County between Lakewood and Tacoma, near to I-5. The spraying will be starting in early May 2026, with work potentially occurring next week.

Spraying will occur over 498 acres in Pierce County, using \(Btk\) to target caterpillars. The area will be treated three times, with applications lasting into May, depending on weather.

Key Details
Method: Low-flying airplanes applying \(Btk\) (a natural soil bacteria safe for pets, bees, and humans).

Scheduling
Applications occur 3–14 days apart, specifically in the morning.

Action Required
Residents should sign up for text or email alerts for the exact day of spraying at agr.wa.gov/moths.

2026 Eradication | Washington State Department of Agriculture

Location
The treatment targets specifically mapped areas near Lakewood.

Weather is the primary factor, and the schedule is subject to change. WSDA advised that treatments are designed to occur in early spring when caterpillars emerge.