Drop in gypsy moths called encouraging

Drop in gypsy moths called encouraging

September 30th, 2011 by Andy Johns in News

A gypsy moth caterpillar walks along a tree branch in Trenton, N.J.

Photo by Associated Press /Times Free Press.

In their battle against killer moths, Tennessee and Georgia officials appear to be gaining the upper hand.

The number of gypsy moths, voracious Asian invaders capable of chomping the leaves off trees, dropped to the lowest number since 1981 in Tennessee.

After collecting their traps this year, forestry officials found only 13 of the bugs in the entire state during their annual sampling.

"Normally we've got from several dozen to several hundreds," said John Kirksey, resource protection unit leader with the Tennessee Division of Forestry. "There's reason to be thinking that things have improved."

Gypsy moths were introduced to New England just after the Civil War and slowly have been spreading south and west ever since, according to the U.S. Forest Service. As caterpillars, the insects feed on hundreds of species of plants, but seem most fond of oak and aspen trees, which they can defoliate completely.

In recent years, crews have battled an infestation on the Hamilton-Bradley county line and others in Bledsoe County. This year, there's no sign of them in either place.

"Usually it takes a couple of years to knock those new places out and we've been successful at it," said Wayne Clatterbuck, professor of forestry, wildlife and fisheries at the University of Tennessee in Knoxville.

Permanent populations have been established as far south as Virginia and were expected to crawl or flutter into Tennessee, as well.

Clatterbuck said that based on predictions, Northeast Tennessee already should be infested.

"That hasn't happened, and we don't really know why," he said. "Ten years ago, I would have said it was the No. 1 threat. Now I'm not so sure."

Kirksey said populations dropped in other states, as well, but he's hesitant to name a cause.

"We'd like to take credit for it, but I'm afraid we can't take full credit," he said.

A wet spring could have contributed to the growth of a bacteria that attacks the moths, Kirksey said. The moisture could also have made the trees healthier and made them less susceptible to attack.

Clatterbuck said it's possible the moths are just at a low point in the species' overall life cycle and the numbers could climb again.

Even in Georgia, where the moths are much less of a threat because of the Peach State's higher temperatures, forest health specialist Scott Griffin said he and others are keeping a close eye out in case the population returns.

"We're still concerned," he said. "It's always a risk of them showing up."