Wednesday, May 16, 2012
A fuzzy white film is imperiling both animals and vegetation in Northwest Georgia.
The culprits are white-nose syndrome (WNS), 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 the Chickamauga and 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 hemlock branches indicates another potential killer. The waxy coat is protective armor of lethal insects, woolly adelgids.
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.
“None have been reported in Catoosa County — yet — but we are starting to see a few in our area,” said Charles Lancaster, county extension agent for the University of Georgia in Ringgold. “They are a booger. They just show up as very tiny, almost cottony pills on the underside of branches. Another sign is that needles will starting looking grayish and thin.”
Lancaster said the spread of woolly adelgids has been expected. The insects have destroyed large stands of hemlocks throughout the southern Appalachians.
Trees at higher elevations might be more at risk, but foresters say any hemlock could fall prey to the voracious insects.
“This is not something that we are used to dealing with, but the main thing is to keep an eye out for them and treat individual trees as necessary,” Lancaster said.
While insecticidal soap sprays can be used on smaller hemlocks, those more than a few feet tall are best treated by soaking soil around the infested tree with an insecticide like Merit.
“Anyone seeing them should contact the extension agency or the forestry commission,” Lancaster said.