May 25, 2022

Spongy Moth Spraying a Success!

Tuesday, May 24th – The Tri-Lakes Special Assessment area was successfully sprayed with Btk after weather had previously postponed the helicopters.

Btk is a biological insecticide and is known only to affect the caterpillars of moths and butterflies that are actively feeding at the time of treatment.  After ingestion, it destroys the caterpillar’s stomach and the insect dies.  After spray, you may notice a change in the Spongy Moth caterpillars after two or three days.  They stop feeding, become sluggish and sometimes mass in sheltered areas.  It may take up to a week for caterpillars that ingested the Btk to die.

Eradication of the Spongy Moth is not possible and should not be expected.  The intent of the spray program is to give heavily infested home areas some relief from the caterpillar nuisance and to protect other areas from outbreaks when feasible.  Homeowners are encouraged to reduce the Spongy Moth population in their area by ground spraying, collecting and destroying egg masses, and destroying caterpillars; but no single method should be relied on for complete control.

Once the spray has dried, the area is completely safe. Drying time averages about 15 minutes, but could take up to 2 hours. 

Photo Courtesy of Dave Lewis – Tri-Lakes Assoc. President