Campus News

Researchers find evidence of exotic beetle invasion

Researchers find evidence of exotic beetle invasion

A pest survey led by researchers at UGA and the Georgia Forestry Commission has found that an exotic wood-boring ambrosia beetle has established a population in the state. The beetle can attack living trees and has the potential to cause economic damage across the country.

And worse, according to Kamal Gandhi, they’re probably here to stay—and increase in number.

“More than likely, we won’t be able to eradicate them from Georgia,” said Gandhi, an assistant professor in the Warnell School of Forestry and Natural Resources.

Gandhi was part of the team that conducted the 2009 Cooperative Agricultural Pest Survey, an annual multi-agency insect sampling that involves the Georgia Forestry Commission, Georgia Department of Agriculture, UGA and the U.S. Department of Agriculture Animal and Plant Health Inspection Service.

The 2009 sampling—detailed in the December edition of The Coleopterists Bulletin—found a troubling number of the camphor shot borer (Xylosandrus mutilatus) in the six counties surveyed. While researchers found just three adult ambrosia beetles in the 2007 survey, they found 56 in 2009. The non-native wood boring ambrosia beetles have been proven to be particularly damaging, with previous studies estimating around $50 million in annual timber losses in some areas in North America. Stowing away in wood packaging around cargo, waste and soil from Asia, the ambrosia beetles also bring with them an exotic pathogenic fungi that can kill trees. Finding them during the CAPS sampling, Gandhi said, worries tree experts around the state.

“This is alarming because they’re also bringing their exotic fungi, they are hard to detect and they can establish their populations quickly in a new area,” she said.

The survey focused on locations in Clarke, Clayton, Douglas, Elbert, Fulton and Oconee counties. The survey was conducted between mid-April and September. None of the beetles were found during the 2008 CAPS sampling.

The CAPS sampling is conducted every year to detect and monitor exotic pests that threaten Georgia’s agriculture and environment. Researchers trapped the camphor shot borers using ethanol and pinene bait, focusing on areas near warehouses and tree nurseries because of the high concentration of imported wood products and waste. The exotic ambrosia beetles can attack more than 200 plant species and a wide variety of native trees.

Gandhi said she and her colleagues don’t know that the beetles have started killing trees in Georgia—but they are fully capable of doing so. The fact that no one is reporting suspicious trees yet indicates that the beetles’ population is still low. More monitoring is needed in the deeper parts of the forests,
she said.