State News

Written by Steven Keith   

SPRINGFIELD — Native to Asia, the tree-killing emerald ash borer is spreading throughout several counties in Illinois.
The small, metallic green beetle has been confirmed in 20 counties in Illinois.
Most recently, the Illinois Department of Agriculture spotted the beetle near Salem in Marion County and at an Interstate 57 rest area in Effingham County.
“The detection in Marion County resulted from a find on one of our purple monitoring traps,” said IDA Spokesperson Jeff Squibb. “There were specimens submitted for testing that turned out to be positive for EAB (emerald ash borer).
“While we were making a site visit to the rural residential location north of Salem, our staff noticed distressed ash trees at a rest area along Interstate 57 in Effingham County, and further investigation discovered beetle larva at the rest stop.”
The larva of the EAB beetle feeds on the inner bark of ash trees, disrupting the flow of water and nutrients of the tree.
According to the IDA website, the EAB is capable of destroying the entire ash tree species in North American, if not controlled. The beetle has already destroyed an estimated 50-100 million ash trees in the United States.
Although the beetle is capable of moving in flight, the IDA thinks it uses transportation corridors to move from one location to another.
“In our experience, when it moves from location to location — most frequently, it’s because of man,” said Squibb. “In other words, it’s because people move infested wood products, including firewood, from one site to another.”
Currently, the United States Department of Agriculture is conducting an internal quarantine “to prevent the man-made spread of the beetle” and “give the time for science to develop a solution,” said Squibb. As part of the federal EAB quarantine, moving firewood outside of several states, including Illinois is illegal.
In the United States, the beetle that migrated from Asia has no natural predators.
“It’s non-native to our country,” said Squibb. “Therefore, there are no natural predators. What that means is there’s no way currently to prevent the beetle from destroying ash trees.”
Treatment chemicals are available for ash trees infested with the beetle. However, the treatment chemicals are not 100 percent effective.
“There are various chemical treatments that are available,” said Squibb. “Some have shown more promise than others. They can certainly prolong the life of the tree, but at this point none of them have proven to be guaranteed 100 percent effective. The department really hasn’t taken a position on the use of such products.”
The beetle is a threat only to ash trees, in the United States.
“In the United States the beetle has feasted exclusively on ash trees, so there’s no threat to crops,” said Squibb. “Here in the United States it has not infested other trees.”
The EAB was discovered in the United States in June 2002, as the cause for the decline of many ash trees in southeast Michigan and neighboring Windsor, Ontario, Canada. Since, the beetle has been discovered in several states, spanning from the East Coast to the Midwest. It was first discovered in Illinois on June 8, 2006, in two ash trees located in "The Windings" subdivision, near Lilly Lake in Kane County.
Adult EAB are about a ½ inch long and leave a D-shaped exit hole in the bark of ash trees when they emerge during the spring season.
Because woodpeckers feed on EAB larva, heavy woodpecker damage on ash trees could be a sign that the tree is infested with the beetle.
To learn more about the EAB, visit www.agr.state.il.us/eab.