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Destructive Tree Insect Beetle: The Emerald Ash Borer

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Emerald Ash Borer There is a division of the United States Department of Agriculture entitled APHIS, which stands for The Animal and Plant Health Inspection Service. This agency oversees protecting animal health, animal welfare, and plant health. APHIS collaborates with other agencies to protect U.S. agriculture from invasive pests and diseases. One if these invasive pests is the Emerald Ash Borer. Much has been written about this incredibly destructive insect that has decimated the ash tree population for much of the Midwest and Northeast U.S. It is slowly spreading farther west and north and has now been found feeding on trees in Winnipeg, Manitoba, Canada. Each month, APHIS releases an updated Emerald Ash Borer Detection Map. This invasive insect has slowly pushed out from its initial infection site in the Detroit, MI area.

What is this Green, Metallic Beetle?

Emerald Ash Borer was first identified in 2002. The adults do little damage to trees, occasionally nibbling on leaves of ash trees. The damage comes from the feeding of the larva, which feeds the inner bark of ash trees and disrupts the trees’ ability to transport water and nutrients to the tree. Emerald Ash Borer is currently found in 31 states* as well as the Canadian provinces of Ontario, Quebec and Manitoba and has literally killed millions of ash trees and has cost many cities millions of dollars in tree removal costs or control methods. The adult Emerald Ash Borer beetles are metallic green and about 1/2-inch long and they only attack ash trees. The female lays individual eggs on ash trees between layers of outer bark and in cracks and crevices of the trunk. The eggs hatch in about two weeks and the larvae bore into the cambium layer of the tree and begin feeding on the phloem tissue. The typical life cycle lasts one to two years. As the larvae feed, they etch serpentine trails that are called galleries. The larvae mature during September, overwinter in small pupation cells and may exit the tree or can feed for another summer the following year before reaching maturity. One aspect of the Emerald Ash Borer life cycle that makes early detection difficult is that the egg laying often occurs in the upper canopy of the tree, making it difficult to find the D-shaped exit holes of the adults. Look for weak and thinning in the upper canopy, branches with yellowing leaves, sucker growth on limbs and trunks, bark splits, and D-shaped exit holes on the trunk.

Treatment for Emerald Ash Borer

There are treatments available for Emerald Ash Borer which require carefully timed applications of insect control materials that are either injected into the surrounding soil or directly into the cambium layer of the tree through an injection process. If you suspect that your ash trees may be suffering from Emerald Ash Borer damage, contact your local Spring-Green. Unfortunately, by the time the canopy begins to thin or sucker growth occurs on the main branches is seen, it is often too late to effectively treat for the insect. Often, tree removal is the only choice. *According to the United States Department of Agriculture: Alabama, Arkansas, Colorado, Connecticut, Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, and Wisconsin