Walker bats, hemlocks under siege

Walker bats, hemlocks under siege

May 16th, 2012 in Local Regional News

A fuzzy white film is imperiling both animals and vegetation in Northwest Georgia.

The culprits are white-nose syndrome, an incurable fungal infection that can be lethal to bats, and the hemlock woolly adelgid, small insects that can kill infested trees over the course of a decade.

Bats found in a cave on Lookout Mountain have tested positive for WNS. This finding occurred after a biologist and volunteers collected two tricolored bats showing symptoms of WNS from a cave that is part of Chickamauga & Chattanooga National Military Park.

White-nose syndrome has killed millions of bats in eastern North America in recent years and is named for the white fungus that forms primarily on the muzzle, ears and wings of infected bats.

Though it is usually transmitted from bat to bat, fungal spores that cause WNS can be carried between caves on human clothing or caving gear. To help prevent inadvertent importation of the pathogen, all park caves have been closed to the public since 2009 and will remain closed indefinitely, officials said.

While the fungus appears not to affect humans, bats are known to carry other diseases such as rabies, so people should not touch any bat, living or dead. Dead, sick or injured bats found within the park should be reported to rangers by calling 423-752-5213.

A cottony coating might be killing bats, but a similar-looking film on a hemlock's branches indicate the protective armor of lethal insects.

"For the past five years or so the adelgid has been sweeping through the Blue Ridge and Smokies - they're finally here," said Norman Edwards, county extension agent for the University of Georgia in LaFayette.

Edwards said affected trees have been found on Lookout Mountain, but the insects are expected to slowly advance throughout the county. The greatest concern is that woolly adelgids will spread into forested areas, weakening and killing trees within a few years following infestation. In this part of the country an infested hemlock's decline and death can occur within three years, particularly if the tree is also stressed by drought, poor soil or other insect pests.

Unlike bats that show signs of WNS, infected trees can be saved. Woolly adelgids can be controlled using chemicals, either as a foliar spray or by systemic application by a soil drench around the base of individual trees.

Since they usually will only be dealing with a few specimen trees, Edwards said homeowners can combat these sap suckers with an insecticide such as Merit.

"They are easy to see in the needles," he said. "They look like white pellets - about the size of a BB - that you can see from maybe 10 feet away. The insect is under that waxy coating.

"Don't get too excited if you see them, but do treat the tree within the next few days."

A systemic insecticide is allowed to soak into the soil surrounding an infested hemlock where it is absorbed and slowly spreads throughout tree, offering protection for about nine months.

"Call the local extension office and we will be glad to talk to homeowners about the treatment," Edwards said.