Scientists seek citizens’ aid in fight to save hemlocks from wooly adelgid

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Another citizen science project for tracking invasive species. Via

Hemlock bough with wooly adelgid.

When Sharon Bryant read an e-mail asking citizens to help find healthy infested hemlocks, she wanted to help. Bryant, a middle school science and math teacher in Lenoir County, had a number of hemlocks in her backyard, all of which were covered with the cottony hemlock woolly adelgid, but a few that were still green and thriving. With a call to researchers at North Carolina State University, Bryant became one of the first citizen scientists to participate in the new “Tiny Terrors” project, designed to collect cuttings from hemlock and Fraser fir trees in an attempt to breed adelgid-resistant trees.

Launched by N.C. State graduate student Erin Mester, the Tiny Terrors project is part of the Alliance for Saving Threatened Forests, a regional effort devoted to developing trees that are able to survive attacks of both balsam and hemlock woolly adelgids, with the hope of restoring the state’s forests. The Alliance is the brainchild of Dr. Fred Hain, entomology professor emeritus at N.C. State. Hain has been studying the balsam woolly adelgid since the 1970s and the hemlock woolly adelgid since 1996.

The balsam woolly adelgid attacks Fraser fir trees, while the hemlock woolly adelgid attacks hemlocks. Both types of trees are mainstays in North Carolina’s mountain forests.

Neither adelgid is native to the U.S., and neither has natural enemies here. In their native lands in Europe (the balsam woolly adelgid) and Asia (the hemlock woolly adelgid), adelgid infestations do not kill trees. In the U.S., however, infested Fraser firs begin showing symptoms of stress in a few weeks and die in two to three years after initial attack. Eastern hemlocks die before they have a chance to reproduce, and the hemlock woolly adelgid attacks hemlocks of any age.

The U.S. Forest Service has deployed a number of biocontrol agents to try to reduce the hemlock woolly adelgid population. However, foresters have found that success of the biocontrol efforts depends heavily on the density of the adelgid population and the health of the trees. Hain hopes that hemlocks that have natural resistance to the hemlock woolly adelgid may make biocontrol more effective.

Although Hain’s team has been experimenting with breeding resistant trees for a few years, they need more natural specimen trees to breed trees that can be planted back in the forest as native trees. Hain and Mester hope that residents will help them do what they personally have neither time nor resources to do: be the eyes in the forest to find appropriate, resistant specimen trees.

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