Beetle release on Mt. Tom aims to curb adelgid infestation

| Written by Julien Vernet

Entomologists from the University of Massachusetts and Virginia Tech released 300 predatory beetles in Mount Tom State Park yesterday, hoping to check an infestation of Asiatic insects that is damaging the park's hemlocks.

Several have been destroyed by the hemlock woolly adelgids, and about 80 percent of the trees have lost branches or canopy cover to the insect, according to Roy Van Driesche, a research professor in the department of Plant, Soil, and Insect Sciences at UMass Amherst.

If all goes as planned he said, the laracobius nigrinius beetles will feed on the adelgids, reducing the pests' population to a non-threatening level. "The only way to check its population is to bring in a predator that feeds on it," said Van Driesche.

Joseph S. Elkinton, a UMass professor of entomology in the same department, said that the adelgid has thrived on Mount Tom partly because the insect is not indigenous to the area. "It's a problem here because the adelgid escaped from the predators that keep it at a low density in the Far East, where it comes from," he said.

But Elkinton noted that the adelgid population is currently at a relatively low level. The past several winters have killed off many of the insects, which are better suited to warmer climates.

The beetles were collected in the Northwest and colonized in a lab at Virginia Tech, whose researchers determined that the beetle could be used to curtail adelgid populations. David Mausel, a graduate student from the school, placed the small beetles on hemlock branches where adelgids were present.

Marking the hemlocks with orange ribbons, the researchers said they will return in a year to gauge the impact of the beetles on the adelgid population.

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