Public advisory: WSDA says check your trees, wreathes for invasive species
Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org

Washington State Department of Agriculture (WSDA) plant protection officials are asking Washington residents to check their trees, wreathes and other purchased winter greenery for invasive species. 

Last week WSDA confirmed elongate hemlock scale, Fiorinia externa, on out-of-state sourced holiday greenery.

“If you find these pests on your trees, wreathes or other holiday greenery, please report it to us and dispose of them immediately,” Benita Matheson, plant services supervisor said.

WSDA experts say to double-bag and dispose of the infested plants.

Elongate hemlock scale (EHS) is an exotic scale insect that prefers hemlock, spruce and fir, but will also feed on cedar, pine and yew.

What does EHS look like?

The flattened, oval shaped insect is light yellow-brown to brownish-orange with a waxy cover. The waxy covers can be observed on the under side of the needle surface as well as on new cones. These waxy strands may be so abundant that it gives the lower surface of infested needles a white appearance.

Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org

What can I do?

Anyone who thinks they have an infested tree or greenery should e-mail [email protected] with images of the infested material and where it was purchased. The plant material should be safely disposed of by cutting it up, double-bagging the pieces and disposing of the bags as trash.

“Proper disposal goes a long way in preventing the introduction and spread of invasive species that could hurt our environment and cause millions of dollars in damage to our economy,” said Justin Bush, executive coordinator of the Washington Invasive Species Council. “Do your part to protect the state you love.”

Residents can prevent introducing invasive species from out of state, such as elongate hemlock scale, by buying a locally grown tree and cut greens, which also supports the local economy.

“Everyone can keep an eye out for species they don’t recognize or symptoms of damage and report what they find. We need the public’s help to quickly detect and respond to newly introduced invasive species before they get out of hand,” Sven-Erik Spichiger, WSDA managing entomologist, said.

History

This armored scale insect is thought to have been unintentionally introduced into the United States from Japan. It was first observed in Queens, New York in 1908. It was most recently detected in Washington on Christmas trees from North Carolina in 2019, but is not known to be established anywhere in Washington.

This pest occurs in Connecticut, Maryland, Massachusetts, New Jersey, New York, North Carolina, Ohio, Rhode Island, and Virginia.