The gypsy moth is a big trouble for forests. With its voracious appetite and ability to move fast across an area, it can wreak havoc on an epic scale. That’s why state officials across the West have aggressive trapping programs to catch and monitor the insect. Recently, Washington state officials made a rare find, which also required some quick action.

Washington officials have been trapping gypsy moths for more than 40 years, but for 2017 they made their first discovery of actively reproducing females during annual summer trapping.

Jim Marra, Washington State Department of Agriculture pest program manager, explains that this find is extraordinary. He adds that there has been evidence of reproducing gypsy moths in the state in the past, but “we’ve never found female moths actively laying eggs in our state. To halt the egg-laying activity and remove this infestation before the caterpillars hatched likely saved our state from an extensive, multiyear eradication project that would have cost millions of dollars. It’s confirmation that our program is working as intended.”

WSDA trappers had nearly 30,000 traps throughout the state this summer, and they recorded an unusually high number of catches in the Puyallup area. When they inspected the location, the team of trappers and entomologists found moths in a residential neighborhood.

In their work, WSDA spent several days collecting female moths and removing vegetation from the site. About 100 females were collected, most of which were actively laying eggs. They also collected several males and egg masses, pupae casings, shed caterpillar skins, and live pupae that had not yet hatched.

Rising numbers
The infestation is higher. For example, by Aug. 11, 80 male moths were trapped in the Puyallup and Graham areas. Last year, only 25 males were found in the entire state.

This find has prompted WSDA to request help from residents and landscapers in limiting potential spread of the pest. Area residents are being asked to thoroughly check any vegetation or outdoor items for egg masses. Movement of egg masses could result in a widespread infestation throughout the state.

If someone finds what they think might be a gypsy moth egg mass, they should contact WSDA for proper identification and removal. There is information about how to identify an egg mass at agr.wa.gov/gypsymoth. If you have a suspected find, you can also call 800-443-6684 or email [email protected].

WSDA first created its gypsy moth trapping and eradication program in 1974. The moths are an invasive pest that feed on hundreds of different trees and bushes, destroying trees in homes, parks and forests.

Source: Washington State Department of Agriculture