OLYMPIA, Wash. — Gov. Jay Inslee issued an emergency proclamation Wednesday because of the "imminent danger" of a spongy moth infestation in Washington state.
In the proclamation, Inslee said the spongy moth infestation is along Steamboat Island Road and US Highway 101 in the Thurston County area and Concrete.
"This imminent danger of infestation seriously endangers the agricultural and horticultural industries of the state of Washington and seriously threatens the economic well-being and quality of life of state residents," Inslee said in the emergency proclamation.
The Washington State Department of Agriculture (WSDA) will begin its treatment to eradicate spongy moths in Thurston County on Friday.
Karla Salp, communications consultant for the WSDA, said these moths can destroy an entire forest. The spongy moth caterpillars feed on over 300 types of trees, plants and shrubs.
“They can defoliate entire forests," Salp said. "I mean, every leaf from the tree canopy down to the ground. I’ve seen entire forests defoliated. It looks like winter in the middle of July because there’s no leaves anywhere.”
Salp said a tree can withstand spongy moths feeding for one year but it will eventually die if the population is allowed to be unchecked. When trees die, Salp said that can lead to damaging "downstream effects" to species in the ecosystem because of the lack of tree canopy.
“It is one of the worst invasive pests that has been introduced to the United States," Salp said. "So far we have been able to keep it down.”
WSDA officials have been monitoring the population of spongy moths in Wahington for 50 years. The spongy moth population is usually below 100 in Washington state, according to Salp.
Last year, WSDA officials caught over 100 spongy moths throughout the state. Salp said 77 of those moths were caught near Steamboat Island.
Salp said the moths arrive in Washington because of transportation and human movement.
The WSDA said in its release that people living near treatment areas can sign up for email, text, or robocall alerts issued the day before treatment is scheduled to take place. You can also email the WSDA Pest Program at pest@agr.wa.gov or call 1-800-443-6684 for alerts.
Salp said three spongy moth treatments will be spaced out in Olympia over a few weeks. Treatments in Skagit County will likely be in mid-to-late May, according to the WSDA. Each treatment takes a couple of hours to complete.
WATCH: Spongy moth caterpillar crawling on a tree
According to the WSDA, the spongy moth is permanently established in 20 states across the Northeast and Midwest, where it has defoliated millions of acres of forest and urban trees.
In 2017, spongy moth caterpillars defoliated one-third of the entire state of Massachusetts. The next year the state lost about one-quarter of its hardwood trees, including three-quarters of its oak trees.