Bad News for the Hemlock Woolly Adelgid

Predator flies released in East Tennessee

by Zoё Hoyle, SRS Science Delivery Group  • 
Forest Service researchers involved in the first eastern U.S. release of the predator fly. From left to right: Kimberly Wallin, Forest Service Northern Research Station and University of Vermont and Bud Mayfield and Bryan Mudder, Forest Service Southern Research Station. Photo by U.S. Forest Service.
Forest Service researchers involved in the first eastern U.S. release of the predator fly. From left to right: Kimberly Wallin, Forest Service Northern Research Station and University of Vermont, with Bud Mayfield and Bryan Mudder, Forest Service Southern Research Station. Photo by U.S. Forest Service.

Over the past decade, the hemlock woolly adelgid, a tiny insect, has ravaged the hemlocks of Southern Appalachia, causing widespread death of the trees that once lined mountain streams throughout the region. Efforts to keep hemlocks alive include releasing insects that feed on the hemlock woolly adelgid, including the Laricobius beetle featured in a recent article on CompassLive.

Now there’s a new biocontrol insect on the scene. On May 11, U.S. Forest Service researchers released Leucopis silver flies on infested eastern hemlocks near Grandview, Tennessee.

In recent years, researchers at Oregon State University and the Forest Service Northern Research Station have been evaluating the potential of two species of silver flies (Leucopis piniperda and Leucopis argenticollis) for biological control of hemlock woolly adelgid.

Leucopis silver fly perched on a hemlock needle on a tree infested with hemlock woolly adelgid. Photo by U.S. Forest Service.
Leucopis silver fly perched on a hemlock needle on a tree infested with hemlock woolly adelgid. Photo by U.S. Forest Service.

The May release, conducted under a USDA-APHIS permit, marked the first eastern U.S. release of the predator silver fly. Researchers will monitor the release sites for predator fly establishment and impact on hemlock woolly adelgid.

 

For more information, email Bud Mayfield at amayfield02@fs.fed.us.

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