| The emerald ash borer, Agrilus planipennis, was discovered in summer 2002 in the Detroit area. It presently is found in a 6 county area of southeastern Michigan, one county in central Michigan, one county in Ontario across the river from Detroit, and one county
in northwestern Ohio. In Michigan it is estimated that 6 million ash trees have already been killed or are dying.
No one knows for sure when or how this exotic beetle became established in Michigan but it is a guess that it has been there for some 5-10 years. The insect is native to China, Korea, Japan, Taiwan, and parts of Russia. It probably was introduced into Michigan from one of those countries in ash wood used as shipping material.
 The
emerald ash borer |
...
not to be con-
fused with the tiger beetle
|
The emerald ash borer adult beetle is a very dark emerald green and is about ½ inch in length. The underside and wing coverings are a dark metallic green color.
In Michigan the adult beetles begin emerging from trees in the latter half of May. The D-shaped emergence holes that measure slightly more than 1/8 inch in diameter can be found on the larger branches and tree trunks. Adults are most commonly seen during the months of June and July on sunny days feeding on the ash foliage or crawling on the branches and trunks of ash trees.
Female beetles deposit eggs in bark crevices during June and July. Eggs hatch in about 10 days, and then the larvae bore into the bark and feed under the bark where they make serpentine mines filled with fine sawdust and frass. The full-grown larvae overwinter in shallow galleries they make in the sapwood. The mature cream-colored larva measures about ¾ inch in length.
Borer infested trees may go undetected until symptoms such as upper tree canopy dieback occurs and the D-shaped emergence holes are seen on the trunk and branches. Depending on tree size the symptoms may not show for a year or a couple of years. In some infested trees a vertical bark split may occur on the trunk. If the bark is removed at such sites, the serpentine larval galleries can be exposed. Trees that are near death often have an abundance of trunk sprouts below the dead trunk tissues.
Throughout the entire Midwest many ash trees are in a state of decline due to such factors as drought, poor growing sites, lilac and native ash borer infestations, and ash yellows, a disease. White ash seems particularly vulnerable. Tree symptoms caused by these factors can be confused with symptoms caused by the emerald ash borer. A native tiger beetle that is a brilliant green and often seen on the ground in open areas should not be confused with the emerald ash borer adult.
If you do find the D-shaped emergence holes in the ash trunk or branches, the very dark metallic green ½ inch long adult beetle, numerous serpentine mines under the ash bark, and many ash sprouts at the base of the tree then contact your local
IL Dept. of Natural Resources Forestry Office or
Extension Office.
Successful containment and eventual control of this beetle will require the utmost vigilance of everyone. All infested areas in Michigan, Ohio and Canada are under quarantine, which prevents the movement of any ash trees, branches, logs, and firewood. The accidental transportation of infested firewood and trees from Michigan are probably the mostly likely ways a new infestation might get started in Illinois.
Intensive studies are underway at Michigan State University and the USDA Forest Service in cooperation with the Michigan Dept. of Natural Resources, Michigan Dept. of Agriculture, and the USDA APHIS PPQ.
This is an extremely dangerous ash pest with the entire ash resource of Illinois at risk. For more information visit the
U.S. Forest Web site, which has additional
links.
James E. Appleby, Phil Nixon, Univ. of Illinois, Dept. of Natural Resources and Environmental Sciences; Charlie Helm, IL Natural History Survey; Kenneth Kruse, APHIS PPQ; and Kathy Sharpe, IL Dept. of Agriculture.
|
