First Release in the Carolinas of New Hemlock Woolly Adelgid Predator

Bryan Mudder releasing biocontrol beetles on infested eastern hemlock tree at Bent Creek Experimental Forest near Asheville, North Carolina. Photo by Bud Mayfield.
Bryan Mudder releasing biocontrol beetles on infested eastern hemlock tree at Bent Creek Experimental Forest near Asheville, North Carolina. Photo by Bud Mayfield.

On Friday last week, U.S. Forest Service scientists with the Southern Research Station and Forest Health Protection released just over 1200 Laricobius osakensis beetles on eastern hemlock trees in North and South Carolina. Reared at University of Tennessee Knoxville’s Lindsay Young Beneficial Insects Lab, the predator beetles are natural enemies of the hemlock woolly adelgid, an invasive insect that kills hemlock trees in eastern North America.

Laricobius osakensis and a related species, Laricobius nigrinus, are being used as biological control agents to reduce populations of hemlock woolly adelgid, with the ultimate goal of increasing the survival and improving the health of infested hemlock trees, allowing them to continue to grow in the mountain landscapes where they often function as a foundation species, shading streams and providing essential habitat to birds and insects.

Laricobius osakensis is of particular interest because it is endemic to the same region of Japan as the adelgid and coevolved with the pest. Last week’s releases near Asheville and Black Mountain in North Carolina, and along the South Saluda River in South Carolina, were the first releases of L. osakensis in these states.

Laricobius osakensis, predator beetle of hemlock woolly adelgid, on hemlock twig. Photo by Bryan Mudder.
Laricobius osakensis, predator beetle of hemlock woolly adelgid, on hemlock twig. Photo by Bryan Mudder.

Through field nursery reproduction and subsequent releases, the Forest Service hopes to establish at each of these locations a growing population of predators that will continually feed on the adelgids, giving hemlock trees a fighting chance.

See more photos of the release on the SRS Field Notes on Forest Pest Research blog.

For more information, email Bryan Mudder at bmudder@fs.fed.us

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