This winter was a brutal one, for sure, but the emerald ash borer still has plenty of life left in it.
Although the Midwest experienced abnormally cold temperatures this winter, it is unlikely that populations of the highly destructive beetle were significantly affected by it, said Adam Witte, exotic forest pest educator in the Purdue University Department of Entomology.
"Headlines have been circulating suggesting that EAB may have met its match," Witte said. "But the EAB, as well as most insects in colder climates, is effective at surviving cold temperatures."
EAB larvae overwintering within ash trees die when temperatures reach minus-28 degrees Fahrenheit below the bark, Witte said. U.S. Forest Service scientists predicting areas in North America where temperatures were cold enough to kill EAB larvae conclude that only parts of Minnesota and North Dakota historically have reached temperatures that low.
Witte said the EAB survives the cold partly because it produces a substance that prevents water in its cells from crystallizing and causing damage, much like antifreeze. Also, insulation provided by the tree bark helps larvae withstand cold temperatures.
Although some parts of the U.S. might have fewer EAB adults emerging in the spring as a result of the cold temperatures, Witte said they probably won't notice. Because of the EAB's high reproductive rate, it likely will be only a matter of time before populations rebound to previous levels.
Despite the cold weather, experts are advising ash tree owners to continue with EAB management plans. One effective means of saving ash trees and reducing costs is to partner with interested neighbors to hire a company to treat trees in their neighborhood. Witte said the collaborative approach likely will reduce transportation and consultation costs for the company, which could lower costs for the property owners.
In Indiana, the EAB has been detected in 69 of its 92 counties. But 79 counties have quarantines against transporting firewood across county lines, with five additional counties in southwest Indiana in the process of establishing the restriction as a result of recent detection of the beetle. Fifteen counties with no detection of it have quarantines because they are surrounded by counties that have the EAB.
Eight counties in southwest Indiana are the only counties in the state where both the EAB has not yet been detected and no quarantines are in place.
For more information on EAB, treatment options, and the organization Neighbors Against Bad Bugs, visit http://extension.entm.purdue.edu/eab/