For WSDA entomologists, August has been an exciting month.
|Trap with 14 male gypsy moths|
By comparison, we found 25 moths total during three months of trapping last year across the whole state.
But for the entomologists and trappers in our Pest Program, the high point was still to come.
An extraordinary find
|Female gypsy moths laying egg masses hidden by a shrub|
The first two team members to arrive had only an empty food carton from Taco Bell, but they quickly put it to use collecting live females. Because European gypsy moth females don’t fly, they were relatively easy to pick up and contain. Male moths tried to fly off, but they were caught mid-air and didn’t get far.
Eventually, more team members arrived with better collection equipment. By the end of the day, 71 female moths were found, several male moths, numerous egg masses, viable pupae, empty pupal casings, shed caterpillar skins and lots of caterpillar frass (poop.)
On follow up visits, about 30 additional females were found, until the bushes were removed on Aug. 4. In total, approximately 100 female gypsy moths were collected.
Processing the material
|Part of the collected specimens after being sorted by WSDA entomologists|
An invasive species scavenger hunt
|WSDA entomologist collects two more female gypsy moths|
While finding live females in infested areas like New England is relatively easy because of their high numbers, that is not the case in Washington where the pest is not established. Because the females don’t fly, finding the one tree or bush where a new infestation is starting is extremely difficult. There are very few clues to point you to where a female gypsy moth may be hiding. So how did WSDA find the infestation this year?
High numbers of male gypsy moth catches alerted WSDA to the problem. The team was able to focus their search in the area of the highest catches. The team also looked for vegetation that showed damage from caterpillar feeding earlier this spring. But adding to the challenge, females aren’t always located on vegetation. They can lay their eggs anywhere – such as outdoor patio furniture, the underside of a brick on a house or inside an old tire, for example – so other surfaces had to be examined as well.
|This just-emerged female's abdomen is full of eggs|
A trapper hung a trap on the tree that morning. By noon, three male moths were already trapped in it. Inspection of the tree showed it had extensive caterpillar feeding on the leaves. When the team member pulled back the bushes at the base of the tree, the infestation was discovered on the concealed base of the tree and within the bushes themselves.
It was a truly exceptional find.
The program works
|WSDA inspects tree and removes infested bushes|
Last year, two male moths were caught less than a mile from the Graham/Puyallup site where the females were found this month. Because of that catch, a high-density grid of 64 traps per square mile was established in the area. The grid enabled the team to target their search more effectively, which led to finding the actively reproducing population.
Trapping continues this year through September, by which time moths will no longer be flying. Because of the work that our gypsy moth program has been doing for decades, WSDA has prevented gypsy moths from becoming established in Washington for more than 40 years.
This discovery is another example of the great work the pest program does to protect our neighborhoods, farms and environment from potentially devastating invasive pests.