Male gypsy moths are darker and smaller than the females. They are a tan brown color and have dark zigzag markings on their wings. They also have distinct, hairy antennae which they use to located females by scent.
Female gypsy moths are a light cream color with wide abdomens and short, thin antennae. Their wings have brown zigzag stripes. European females do not fly, while Asian gypsy moth females can.
In response to an uptick in mature gypsy moth prevalence in Western Washington, the state Department of Agriculture is proposing a treatment program that would begin in the spring of 2018.
That program would include two separate treatments intended to eradicate young gypsy moths, which are an invasive pest that are known to kill trees. The proposal aims to treat a total of about 1,300 acres in Pierce and Kitsap counties.
The treatment program proposed by the WSDA would use aerial applications of a naturally occurring soil bacteria called Bacillus thuringiensis var. kurstaki, or Btk. The bacteria is used as an insecticide and is approved for use in organic agriculture. A press release from the WSDA notes that Btk “has had a proven safety record around people, plants, pets, fish, birds and bees.”
The applications would likely be done in April or May as gypsy moth caterpillars emerge and begin to feed on trees and shrubs.
Last summer during an annual trapping program, the WSDA caught 117 male gypsy moths, the majority of which were found in Pierce and Kitsap counties. That was the highest number of gypsy moths recovered in more than 20 years. The WSDA will now prepare environmental reviews, consult with local, state, and federal agencies and attempt a public outreach in regard to their plan. The release from the WSDA noted that the proposal for 2018 is only a fraction of the size of a similar eradication effort that took place in 2016. That action covered 10,000 acres with Btk treatments. The WSDA reports that no new gypsy moths have been found in those areas since those treatments.
“For over 40 years our gypsy moth program has been protecting Washington’s neighborhoods, parks and forests from this destructive pest,” WSDA Pest Program Manager Jim Marra said in the release. “We have a very effective detection and treatment program. I’m confident that our proposal will prevent gypsy moth from gaining a foothold in our state and protect our environment from this invasive threat.”
European gypsy moths have established permanent populations in 20 states and have been blamed for the destruction of millions of acres of trees. Just this year gypsy moth caterpillars were responsible for the defoliation of one-third of the entire state of Massachusetts.
Updates will be posted online at agr.wa.gov/gypsymoth including specific information on treatment areas and public comment opportunities.
