Articles

Ash tree nemesis bores into Illinois: Beetles that could kill 130 million of state's trees turn up in Kane County.

Chicago Tribune (Chicago, IL); 6/14/2006

Byline: Michael Hawthorne and James Kimberly

A tiny, metallic green beetle that has killed millions of ash trees across the Midwest has been quietly 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. Ravenswood infestation halted

The Illinois 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 last 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.

People likely helped spread the ash borer to the Chicago area by unwittingly carrying infested firewood, Cinnamon said. Indiana officials announced earlier this week that the bug arrived in the South Bend area the same way. Once the extent of the Kane County infestation is determined, state officials said they would impose a quarantine that prohibits the movement of ash logs, nursery stock or firewood into or out of the area. "We need an absolute zero tolerance for movement of any ash products," said Steve Knight, state plant health director for the Animal and Plant Health Inspection Service, an arm of the U.S. Department of Agriculture. "That is the most effective tool we have." 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 is usually 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. "There are native beetles and diseases that can cause the same type of damage, so it can be difficult to figure out if it's the ash borer," said Joe McCarthy, senior forester in the Chicago Bureau of Forestry. The insect is believed to have arrived in Detroit several years ago as an unintentional stowaway in wooden packing materials, the same way the Asian longhorned beetle came to Chicago. Native to northern China, eastern Russia, Mongolia, Japan and Taiwan, the ash borer is considered a minor pest in those countries, where trees have developed natural defenses to keep it in check. Adult ash borers--each barely larger than a thumbnail--gnaw their way out of trees in early June looking for fresh bark to lay eggs upon for another destructive generation. Once the larvae hatch, they burrow into the tree and carve serpentine tunnels in the phloem and outer sapwood. Trees eventually die because the bugs cut off the movement of nutrients through the tree. The bugs only attack ash trees, a hearty and durable source of shade planted heavily in cities after Dutch elm disease nearly wiped out the stately American elm by the 1960s. The new pest so concerns Chicago officials that they stopped planting ash trees in October 2003, when the scope of the Michigan infestation became clear. In Kane County, ReBecca Mathewson suspected the worst after learning about the pest from an arborist she called when two towering ash trees in her half-acre lot failed to fill out with leaves last summer, the way they had in the past. During the spring, she paid the arborist $165 to inject chemicals into the trunks. But the 30-year-old trees still stood as bare as December. Then last week she found a green bug dangling from a spider web in the sickly ash tree in her back yard. Mathewson captured the beetle in a jar and called the federal Agriculture Department office in Des Plaines. They told her to freeze it and send it along for identification. Loss of tree canopy feared Mature trees and spacious lots drew Mathewson and her husband, James, to the subdivision west of St. Charles from their home in Winnetka three years ago. She is devastated by the thought of losing the trees. "We didn't want a sun-drenched lot," she said. "We wanted the tall trees." Across from Mathewson's house, the ash trees that provided scenery for 11 summers and brilliant colors for 11 falls to Barbara Aghbabian are now bare and sickly. The trees were beautiful last summer and gave no indication that there were problems lurking just below the bark, she said. "The neighborhood is what made us buy here. We liked all the trees. We didn't want to buy a house in a cornfield," she said. If there is any silver lining, she said, it is that the beetles limit their attacks to ash trees. The towering oaks, maples and locusts that fill the large yards up and down her street will be spared, she said. "I'm just so happy they don't eat other trees," she said. "That was my biggest concern, 'Oh my gosh, am I going to lose all my trees?'"