Arborists and tree care professionals throughout the Midwest and the Appalachians are gearing up to fight the emerald ash borer (EAB) and the hemlock woolly adelgid (HWA), insects that are killing ash and hemlock trees, respectively. To help educate and better prepare professionals to combat these devastating pests, the Invasive Pest Field Day training session was held at Longwood Gardens in Kennett Square, Pa., Nov. 13.
As the final installation of a four-part series, the Pennsylvania field day followed events in West Bloomfield, Mich., Aug. 16; Asheville, N.C., Aug. 28; and St. Charles, Ill., Sept. 26. Each location brought around 100 municipal arborists, city foresters, tree care professionals, state extension agents and university researchers.
Hosted by Bayer Environmental Science and Arborjet, the Invasive Pest Field Day was a free, one-day event where professionals heard a series of lectures presented by local experts on the management of emerald ash borer and hemlock woolly adelgid. Topics included current information on pest biology, management in natural settings, survey updates and current quarantine and compliance agreement information, the efficacy of insecticide treatments, and building a tree care business on insect management. Additionally, attendees participated in hands-on demonstrations of the latest application techniques.
Speakers included Casey Sclar, Ph.D., of Longwood Gardens; Shahla Werner, Ph.D., of the Pennsylvania Department of Conservation and Natural Resources; Sven-Erik Spichiger of the Pennsylvania Department of Agriculture; and Rick Turcotte of USDA Forest Service. Bob McMullin of Keystone Tree in Pennsylvania, Wayne White of Emerald Tree Care and Dave Sutton of Tri-City Tree Doctor in Michigan also spoke about building a tree care business through EAB and HWA treatment.
Although HWA has plagued 47 counties within the Pennsylvania landscape over the past 40 years, this past June EAB was also discovered within state borders. Emerald ash borer is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. Since its introduction, EAB has killed nearly every ash tree in southeastern Michigan, has spread to 40,000 square miles across Ohio, Indiana and southwestern Ontario, and has recently been detected in Illinois, Maryland, West Virginia and western Pennsylvania. The potential impact in Pennsylvania could be devastating.
The pest’s rapid spread is attributed to the transport of firewood or ash logs from infested regions to outlying areas. Additionally, EAB can fly up to two miles in search of a host tree. The larvae bore into and feed on the vascular tissue of ash trees, disrupting the tree's ability to transport water and nutrients. To date, efforts to eradicate local infestations of the pest by quarantine and cutting down all ash trees in infested areas have been unsuccessful. Throughout the Midwest, more than 20 million ash trees have been killed and in many cities, the only remaining ash trees are those that were treated with products containing imidacloprid.
Because the insects have no natural enemies in the United States, nothing prevents EAB and HWA from infesting ash and hemlock trees. Soil drenching or injection of imidacloprid is a widely used and effective treatment, from which the trees are expected to remain clean for at least a year after eliminating the infestation.