Emerald Ash Borer Surveillance Results, 2012

The following news release was sent Wednesday, September 12, 2012, from the Iowa Department of Agriculture & Land Stewardship, the Iowa Department of Natural Resources, and Iowa State University Extension and Outreach.

DES MOINES - The Iowa Emerald Ash Borer Team today said that results from surveillance efforts undertaken again in 2012 show little movement of the emerald ash borer (EAB), an invasive pest that kills ash trees. The pest had initially been found in Iowa along the Mississippi River in Allamakee County in 2010 and this year’s survey results show the pest has not moved outside of Allamakee County.

The Iowa EAB Team continues to discourage homeowners more than fifteen miles from known infestations from treating their ash trees with insecticides to protect them from this pest. This would be nearly all of the state at this time. Unfortunately, some tree care companies are distributing inaccurate information and recommending insecticide treatments for healthy ash trees located as far away as central Iowa.

EAB management recommendations (Pm-2084) for homeowners are available from Iowa State University Extension and Outreach. 

The EAB Team in Iowa has been conducting annual surveys to determine if this pest is in Iowa since 2003. Efforts have included visual surveys, sentinel trees, trap surveys, nursery stock inspections, sawmill/wood processing site visits, and educational programs.

This summer, USDA APHIS PPQ placed nearly 1,200 purple sticky traps in an effort to monitor the spread of EAB; most of these traps were placed in eastern Iowa. Two traps in Allamakee County, one in New Albin and another in Lansing, each caught one beetle. “The Iowa EAB Team is not surprised by the two positives in Allamakee County as it has been quarantined for two years. We are pleased that other traps did not pick up any infestations outside of Allamakee County in our latest surveys.” said Robin Pruisner, IDALS State Entomologist.

In addition to the purple traps, the Iowa Department of Natural Resources is in the process of evaluating 416 sentinel trees for signs of infestation, and conducted visual inspections of 1,291 trees in 58 counties for signs of EAB infestation. “We continue to monitor for EAB throughout the State, we have also completed 110 community urban forest inventories and Community Forest Management Plans to assist communities with preparing for and dealing with EAB and other pest issues. Current plans are to complete another 120 community inventories and plans over the next two to three years.” said DNR State Forester Paul Tauke.

“With the new results in Allamakee County, Iowa State University Extension and Outreach is suggesting that preventive treatments for individual healthy ash trees could be done in New Albin, and Lansing, IA,” said Mark Shour, ISU Extension Entomologist. “Other communities outside 15 miles of the known infestations should be prepared to begin preventive treatments in 2013 if additional evidence of EAB is found in eastern Allamakee County.” 

For trees with 25” circumference (~8” diameter), homeowners can treat their own trees following the recommendations of ISU Extension and Outreach. If a tree is larger than that size, a commercial pesticide applicator should be called for assistance. Treatments will need to be done every 1-3 years for the life of the tree to maintain protection. As a reminder, insecticide products to manage EAB work best as preventive treatments for healthy ash trees planted along streets or in yard settings. Healthy trees have full crowns, elongating branches, and bark tightly held to the trunk/branches. It is not practical or cost effective to treat woodlot trees with insecticides.

A federal and state quarantine has been in place for Allamakee County since 2010. The quarantine prohibits the movement of firewood, ash nursery stock, ash timber, or any other article that could further spread EAB. 

The Emerald Ash Borer (EAB) is native to eastern Asia, and was detected in the United States near Detroit, Michigan in 2002.  EAB kills all ash (Fraxinus) species by larvae burrowing under the bark and eating the actively growing layers.

The metallic-green adult beetles are a half inch long, and are active from late-May to early-August in Iowa. Signs of EAB infestation include one-eighth inch D-shaped exit holes in ash tree bark and serpentine tunnels packed with sawdust under the bark. Tree symptoms of an infestation include crown thinning and dieback when first noticed, epicormic sprouting as insect damage progresses, and woodpecker feeding.

EAB has killed ash trees of various sizes in neighborhoods and woodlands throughout the Midwest. Ash is one of the most abundant native tree species in North America, and has been heavily planted as a landscape tree in yards and other urban areas. According to the USDA Forest Service, Iowa has an estimated 52 million rural ash trees and approximately 3.1 million more ash trees in urban areas.

The Iowa Emerald Ash Borer Team includes officials from the Iowa Department of Agriculture and Land Stewardship, Iowa State University Extension and Outreach, the Iowa Department of Natural Resources, USDA Animal Plant Health Inspection Service (APHIS) and the USDA Forest Service.

The movement of firewood throughout Iowa and to other states poses the greatest threat to quickly spread EAB even further.  Areas currently infested are under federal and state quarantines, but unknowing campers or others who transport firewood can spark an outbreak. As a result, officials are asking Iowans to not move firewood and instead buy and burn it locally.

To learn more about EAB please visit the following websites:

     Iowa Tree Pests

     Iowa Department of Natural Resources

     Iowa State University Extension & Outreach


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on September 12, 2012. The information contained within may not be the most current and accurate depending on when it is accessed.