Spring brings emergence of Emerald Ash Borer

By on June 5, 2009

REGIONAL—Since June 2006, the Emerald Ash Borer has been an insect problem for northern Illinois trees.

The Illinois and U.S. Departments of Agriculture are working with communities and industry to try to control the spread. The Emerald Ash Borer only affects ash trees.

“Along with the official efforts, there are things that individuals can also do to help prevent the problem from spreading,” said John Church, University of Illinois Extension Educator, Natural Resources, Rockford.

First, become a good observer. This is the time of year when adults will start to fly to find egg-laying sites, so their presence may be noticed on trees. The Emerald Ash Borer is a small metallic-green insect, approximately one-third to one-half the size of a penny. Adults can fly but usually not for long distances. They lay eggs in the bark of the tree and when the borer hatches, it will tunnel under the bark and start feeding on the sapwood of the tree, causing leaves to thin and yellow and eventual dieback of the limbs.

There are other metallic-green insects including many beetles. The false June bug is a common metallic-green beetle, though it is almost the size of a quarter. Japanese beetles are metallic green as well, but with a coppery overtone.

Besides the color, D-shaped holes in the bark are also a clue. No other insect creates the BB-size D-shaped holes on ashes. These are emergence holes for the adults after tunneling under the bark as larvae. Watching the trunks of trees for these exit holes is important as it is one of the first signs of infestation.

Often, by the time the tree shows any dieback, the damage may be very extensive. Also, as tops die back, the trees may produce shoots around the trunk at ground level which is another indicator since other problems such as wilt diseases seldom have this characteristic. Unfortunately, trees may have been infested for several years before outward symptoms are noticed.

Areas identified with the Emerald Ash Borer are officially quarantined to restrict the movement of wood, wood products and the borer. However, individuals can follow similar guidelines voluntarily in other areas to help prevent the spread.

One of the major helpful things to be done is to only use local firewood and don’t bring in firewood or other ash wood products from infested areas or from a long distance. If camping in infested areas, leave unused firewood at that site. New regulations went into effect on Jan. 1, 2009, for commercial firewood vendors.

Some preventative insecticide treatments may also be used on ash trees, but its effectiveness depends on the tree, its condition and the proximity to other infected sites.

Another long-term preventative measure is to always plant a variety of well-adapted trees in the landscape to avoid a high percentage of any one kind of tree that may all become infested with a particular pest.

For more information, visit
or www.agr.state.il.us/eab.

These sites contain information
regarding most aspects of the pest,
including video clips, identification
information, quarantine areas,
regulations, etc.