SANDPOINT, Idaho – The Idaho Department of Lands (IDL) confirmed the invasive spongy moth’s presence in Sandpoint for the second year in a row. This marks the first potential population detection in the area since 1991.
Spongy moth caterpillars, which feed on a variety of trees, are not established in Idaho. However, new introductions can occur through accidental transport on firewood, RVs, or outdoor gear.
In 2024, a male European spongy moth was found in a monitoring trap near Oak Street and Division Avenue. In 2025, follow-up trapping led to the capture of three more moths near Monroe and Poplar and the confluence of Syringa Creek and Chuck Slough. DNA analysis confirmed these as male European spongy moths.
Erika Eidson, IDL Forest Health Specialist, highlighted the unusual nature of these captures. “Over the years, more than 20 similar initial spongy moth detections have occurred throughout many Idaho communities, additional moths have not been caught in any follow-up delimitation trapping since 1994,” she said. The captures raise concerns about a possible reproducing population.
Ground surveys in fall 2025 found no egg masses or feeding damage, suggesting a very small population. Past infestations in Sandpoint and Coeur d’Alene were eradicated between 1986 and 1991.
In 2026, IDL will intensify trapping efforts to monitor the situation. Plans include placing 50 traps per square mile within 0.5 miles of positive capture sites and 36 traps per square mile in surrounding areas.
Residents will notice bright green or orange traps next summer and are urged not to disturb them. For inquiries, contact the Idaho Department of Lands.
To prevent the spread of invasive insects, avoid moving firewood long distances and inspect outdoor objects for signs of insects. Report suspicious sightings to the Idaho Department of Lands.
