BENT CREEK EXPERIMENTAL FOREST, N.C. — When the woolly adelgids come and descend on the forest, the eastern hemlock dies.

It’s been like this since the insect was discovered in Virginia in 1951. The aphid-like pest spread north first, but by the early 2000s, eastern hemlocks in the southern Appalachians were being decimated by the insect native to East Asia. By some estimates, 90 percent of the tree species’ range has been affected.

Researchers here are hatching a plan to stop the woolly adelgid. A 1-acre plot of forest is the site of a budding insectary, a farm in the trees of the predator beetle Laricobius nigrinus that has been shown in some cases to kill the adelgid.

Read more: http://www.scientificamerican.com/article/an-army-of-beetles-could-save-dying-hemlock-forests/