My friends at Public Health – Seattle & King County wanted me know about a gypsy moth eradication project planned by the Washington State Department of Agriculture (WSDA) for Tukwila and Renton this year. They figured our hot line staff could help if you called, so we had a crash course in these hungry pests.
I learned that the European gypsy moth is the most damaging forest insect pest ever introduced into North America. Yes, introduced—it is not native to Washington State. You know what a mess tent caterpillars make of our landscape? Well, the gypsy moth is much more destructive and can defoliate hundreds of thousands of acres of forest in a single year. Forest defoliation destroys wildlife habitat, increases the risk of wildfire, affects water quality, and can disrupt stream habitat for migrating salmon. There is no way I want to see Washington State without our forests, wildlife, and salmon!
For such a little pest it has a huge impact on our economy, and not in a good way. If the gypsy moth becomes established, costly quarantines will be imposed on our state’s nursery, forestry, and Christmas tree industries. Also, states with permanent populations of the gypsy moth spray 1,000 times more pesticide in a single year to suppress them than Washington does to eradicate it. No one wants more pesticides.
I also discovered that Gypsy moth caterpillars can trigger allergic reactions in some people, causing skin welts, rashes, and swelling. The gypsy moth is more of a health threat than the products used to get rid of them!
For over 30 years, WSDA has successively prevented the gypsy moth from spreading to our state by eradicating small isolated populations. So, how do they do this and still keep Washington residents safe?
First, they eliminate gypsy moth caterpillars using a biological insecticide, Btk, on trees and shrubs in the area around the egg mass locations. Btk is a naturally occurring soil bacterium (meaning it is already in the dirt). It affects only caterpillars and has been used for decadesto control the gypsy moth. Relax Dudette, you and your kids aren’t caterpillars, so this is not toxic for you.
Then, they stop the mating cycle with a pheromone or sex attractant that confuses male gypsy moths so they cannot find female gypsy moths to mate with—effectively stopping egg production. Since between 500 and 1,000 gypsy moth caterpillars can emerge from a single egg mass it is very important to prevent the boy moths from finding the girl moths and reproducing. Pheromones target a specific species, in this case, the gypsy moth. Dude, stop sweating it, you aren’t a gypsy moth; it’s not going to affect you.
The gypsy moth feeds on more than 500 species of trees and plants and reproduces very rapidly. Visit the Washington State Department of Agriculturefor more information on the gypsy moth program or call the gypsy moth toll-free hotline at 1-800-443-6684.
If you have any questions about Btk or pheromones, or think you’ve been exposed to them, give my friends at the Poison Center a call at 800-222-1222. And be glad you aren’t a gypsy moth—they aren’t very popular!