Scientists looking for tree-killing pests

April 15th, 2011

Scientists looking for tree-killing pests


Something unusual has been spotted sprouting from local trees.

Residents may have noticed the appearance of purple boxes hanging in branches of trees throughout Blount County. They’re part of a U.S. Department of Agriculture project to track the possible spread of the non-native emerald ash borer, a type of tree-killing beetle that can travel undetected in firewood and nursery stock from quarantined areas of the country.

Elizabeth Long of the University of Tennessee Entomology and Plant Pathology Department said that contractors are putting out 4,300 of the traps within a 50-mile radius of a site on the Knox County/Loudon County line where the beetles were discovered in 2010.

“They are doing a follow-up survey to try to find out where the beetle may be,” Long said. “We’re hoping not to find it, of course.”

The beetle traps are pretty easy to spot, Long said. “They are so obvious and people do notice them. The contractors should be checking them every couple of weeks through August.”

Last year was not a good year when it came to the discovery of invasive pests in East Tennessee. The discovery of the emerald ash borers came within 10 days of the announcement that researchers had confirmed the presence of the devastating thousand cankers disease, which kills black walnut trees, in Knox County. Shortly afterward, it was discovered in Blount County, which is now under a quarantine prohibiting the movement of firewood and black walnut nursery stock and limiting the movement of black walnut timber and other material that can spread the disease.

The thousand cankers disease-causing fungus, Geosmithia, is transmitted by a small twig beetle. Branches and trunk tissue are killed by repeated infections by the fungus as the beetles carry the fungus into new bark.

An outbreak of the disease was discovered in Knox County in July by a state forester. It was the first detection of the destructive tree pest east of the Mississippi River. Scientists who study the disease have described the discovery as a “death sentence” for the black walnut trees in the affected counties.

It’s not that East Tennessee hasn’t already been a battle ground against invading alien species. University of Tennessee scientists are developing ways to deal with the hemlock woolly adelgid in the Great Smoky Mountains National Park.

Caves in the Park are also quarantined because of presence of a fungus called Geomyces destructans, which is believed to cause the bat-killing White Nose Syndrome.

“I don’t think we’ll be out of a job any time soon, unfortunately,” Long said.

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