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Keeping Emerald Ash Borer Out of PA - June 2005

June, 2005

UNIVERSITY PARK, Pa. - When a new exotic pest from Asia was detected in Michigan three years ago, state agencies in Pennsylvania formed a collaboration to keep it out of the commonwealth.

Emerald ash borer was first discovered in North America in southeastern Michigan in 2002. According to Mike Blumenthal, forest health supervisor with the Pennsylvania Department of Conservation and Natural Resources (DCNR), the larvae of the beetle primarily feed on the tissue under the bark of ash tees, causing the death of branches and entire trees. "In Michigan alone, over seven million ash trees have been lost to the pest," he says.

Since its discovery in Michigan, the beetle has been detected in Ohio, Maryland, Virginia, Indiana and neighboring areas in Canada. The DCNR Bureau of Forestry, along with US Department of Agriculture/Animal Plant Health Inspection Service, US Forest Service, Pennsylvania Department of Agriculture and Penn State Cooperative Extension assembled a task force to detect and control this invasive threat. Staring in 2003, the Bureau of Forestry began surveying for the invasive pest on state-owned forestlands, parks and gamelands. The first survey site was in Erie County due to its close proximity to Michigan, high population of ash trees, and because it is a port of entry.

In 2004, the survey program was expanded to include twenty inspections sites. According to Sven-Erik Spichiger, forest entomologist with DCNR, the sites were chosen based in part on state park visitation records. "Many campers like to bring their own firewood, which can spread an exotic pest like emerald ash borer. We looked at parks that had high visitor numbers from Michigan and Ohio, where the beetle has already been detected," he explains. Also included in the survey were state parks with high numbers of ash trees. The results have been negative so far, suggesting that the emerald ash borer has not reached Pennsylvania. "However, several native pests of ash were detected in traps including the redheaded ash borer and many species of bark beetles," says Spichiger. The surveying efforts will continue in 2005.

The spread of emerald ash borer has been linked to the transportation of infested nursery stock and firewood. To help prevent its spread, Spichiger recommends homeowners landscape with native plants and buy firewood locally when camping. "If you have already transported firewood, the best thing to do is to burn it," he says.

In addition, Spichiger recommends people be on the lookout for the exotic pest while in the woods and in their backyards. "Adult emerald ash borers are easy to spot. They are larger and a brighter green than any other native American species, and are slender and slightly less than one inch long," he explains. Spichiger says eggs are laid between layers of bark and in bark crevices. Larvae, slightly longer than the adult beetle and cream-colored, hatch in about one week and bore into the tree, creating "S" shaped markings. "After three feeding stages, the larvae will excavate a pupal chamber in the fall, where they will overwinter. Adults begin to emerge in late spring through "D"-shaped exit holes and remain active until the end of summer."

Spichiger says it is also important to be able to identify ash trees, the only known host of the emerald ash borer. "The pest is known to infest all species of ash, which can be identified by their opposing branches and compound leaves. Older ash trees will have a characteristic diamond pattern on their bark."

Currently, there are no effective treatments for trees infected by emerald ash borer. "Natural enemies are not effective, since the beetles are so prolific," says Spichiger. "Once a tree is infested, the only way of preventing its spread is to establish a 'no ash zone' in which all ash trees are removed within a half-mile radius of the infected tree," he explains. In addition, chemical insecticides are not effective because beetles in colder regions will often have a two-year life cycle. "With a two-year live cycle, there is no way of knowing when to best apply the treatments. However, research on other treatment options in states where the beetle has already been detected is currently underway."

According to Spichiger, the beetle could cause widespread devastation to the ash tree industry. "Currently the industry in the US is valued at 16 billion dollars a year, with the wood being used for baseball bats, ax handles, and many other uses," he explains.

Spichiger stresses it is very important for people to be aware of this invasive pest. If you think you have found an emerald ash borer, you can report it by contacting the PDA at 717-772-5228, or email at Badbug@state.pa.us.

For more information on emerald ash borer, see the US Forest Service's Web site at http://www.na.fs.fed.us/spfo/eab/. For more information on invasive species, including the emerald ash borer, see Penn State's Department of Entomology Web site at http://www.ento.psu.edu/extension/invasive/default.htm. In addition, the brochure "What is the Emerald Ash Borer?" is now available from the Pennsylvania IPM Program's Web site as a downloadable PDF file at http://paipm.cas.psu.edu.

The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and nonagricultural situations. Integrated pest management, or IPM, aims to manage pests -- such as insects, diseases, weeds and animals -- by combining physical, biological and chemical tactics that are safe, profitable and environmentally compatible. For more information, contact the program at (814) 865-2839, or visit their Web site at http://paipm.cas.psu.edu. To view our archived news releases, see Web site http://paipm.cas.psu.edu/newsrelease.html.