A tiny, metallic green beetle that has killed millions of ash trees across the Midwest quietly has been multiplying for at least three years in a heavily wooded Kane County subdivision.
The discovery of the emerald ash borer, announced Tuesday by state and federal officials, is the first evidence of a long-dreaded infestation that could threaten more than 130 million trees in Illinois and a fifth of Chicago’s leafy cover.
Since they were found in suburban Detroit four years ago, the fast-spreading beetles have killed more than 15 million ash trees in Michigan, a staggering number compared with the 1,500 trees destroyed in Chicago by another imported pest, the Asian longhorned beetle.
Illinois officials thought they had dodged the ash borer. But a homeowner in the Windings of Ferson Creek subdivision west of St. Charles called last week to ask about a slender green bug she found snared in a spider’s web in a dying ash tree in her yard.
State inspectors came out and found hundreds of exit holes left by adult ash borers in a half-dozen trees, indicating the bugs have been around for at least three years and perhaps for as many as six. The inspectors plan to fan out across the area during the next two weeks searching for more infested trees.
“Early detection of the emerald ash borer is critical, and we need everybody’s help to find it,” said Mark Cinnamon, manager of nursery and northeastern field operations for the Illinois Department of Agriculture.
State and federal officials said they still are figuring out what to do next. In Michigan, every ash tree within a half-mile of the area where the beetles are found is cut down, fed into a wood chipper and burned.
The local discovery comes a year after authorities declared victory in their fight against the Asian longhorned beetle, which stripped parts of Chicago’s Ravenswood neighborhood of its century-old canopy.
Most of the arborists and foresters on hand for Tuesday’s announcement in the Kane County Government Center in Geneva have seen how the ash borer has robbed entire blocks of their shade in parts of suburban Detroit. Although they’ve spent much of the past two years preparing for the beetle to arrive here, they sounded grim about the new bug battle facing them.
“If the experience of Michigan, Ohio and Indiana is any indication, the emerald ash borer is a much more difficult pest to deal with, and therefore control will be difficult,” said Warren Goesch, manager of natural resources for the state Agriculture Department.
Bug-eyed
What makes tracking the ash borer so difficult is that it can take several years before the damage becomes evident. The bugs typically attack the top of a tree first. By the time it becomes obvious that a tree is infested–the telltale signs are dying branches and shoots that pop out desperately along the trunk–it usually is too late to save it. There are some treatments available for healthy trees, but the pesticides are of no use if ash borers already are burrowing their way beneath the bark of a tree.
