Triangular, purple kite-like contraptions placed in trees across the country are helping state and federal agriculture officials learn more about a deadly beetle that has killed tens of millions of ash trees in the United States and Canada and threatens countless more.
The 61,500 traps installed in 48 states are part of a survey led and funded by the U.S. Department of Agriculture to track the emerald ash borer, a species native to China and eastern Asia that was first detected in the U.S. in 2002. The invasive pest likely arrived inside wood packing material from Asia and has since been detected in 15 states through the national survey using the purple traps that has been done annually since 2008.
Currently the USDA has quarantined West Virginia, Pennsylvania, Indiana, Illinois and the lower peninsula of Michigan. Certain areas of other states, like Virginia, also have quarantines, which means that ash trees, logs or nursery trees cannot be transported out of that specific area.
The 2011 survey shows the tiny, green beetle hasn't been detected outside of the states where it's already known to exist, but the bug has been found in about 60 more counties in those states, said Sharon Lucik with the USDA's emerald ash borer program. Some states have not yet completed their reports.
"I don't know that we can say no news is good news, because we know that the beetle in low populations is difficult to detect," Lucik said, adding that the most important aspect of the survey is that they are learning more about the emerald ash borer. "With each new survey year we are acquiring a better understanding of where the pest is. ... We are fine-tuning how it spreads naturally."
The danger to all 16 native species of ash trees comes from the bug's larvae, which tunnel beneath the bark, disrupt the tree's ability to take food and water and eventually starve and kill it. The agricultural impact to states where the beetle has been detected could be substantial and other effects include decreasing property values, losing the ash wood supply and decreasing air quality, Lucik said.
The unusual, 2-foot-tall traps that resemble a wayward kite are placed in trees during the spring and summer months, and are then taken down in the fall. The traps' outer walls are smeared with glue. Inside hangs a plastic bag of pungent manuka oil, broadcasting the scent of a distressed ash tree to insects.
Besides attracting the beetle, the purple color also elevated public awareness of the problem.
Lucik said people driving in their cars have seen the traps and curiosity gets the best of them, they'll pull over and get out of their car and call the hotline number listed on a sign that says, "Do Not Disturb. USDA Emerald Ash Borer Survey."
Public awareness of the issue is particularly important this time of year as the insect can be unknowingly transported in firewood and other products.
"Think of how many miles people travel when they go on vacation, camping, or recreating. So that's why the human-assisted movement of infested material really expands substantially the widespread area where the emerald ash borer currently has been found," Lucik said.
The USDA plans to do the survey again in 2012 and also is looking at using stingless wasps, a natural enemy, as a possible biological control for the beetle.
The states where the insect has been detected are: Michigan, Illinois, Indiana, Iowa, Kentucky, Maryland, Minnesota, Missouri, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Wisconsin. It also has been discovered in Ontario and Quebec.
Michael Felberbaum can be reached at http://www.twitter.com/MLFelberbaum.