Emerald Ash Borer Found in Fayette and Madison Counties, Iowa

Iowa now has 45 infested counties

April 5, 2017, 8:02 am | Dustin Vande Hoef, Julie Sparks, Laura Sternweis

DES MOINES – The emerald ash borer can now be linked to 45 counties in Iowa as Fayette and Madison counties are the most recent to be added to that growing list. EAB is a destructive wood-boring beetle that attacks and kills all ash tree species. This exotic pest was first discovered in Iowa in 2010.

Emerald Ash BorerIn Fayette County, the insect was discovered in a city-owned ash tree in Oelwein. For Madison County, the finding took place in a rural area south of Winterset. Insect specimens taken from these sites were confirmed as EAB by a federal identifier.

“This year we have already had six new counties confirmed with EAB,” said Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB and gypsy moth coordinator. “I anticipate this number to only grow throughout 2017, passing last year’s mark of 10 new county finds.”

The Iowa EAB Team provides EAB diagnostic assistance to landowners and includes officials from Iowa Department of Agriculture and Land Stewardship, Iowa State University Extension and Outreach, the Iowa Department of Natural Resources, USDA Animal and Plant Health Inspection Service and the USDA Forest Service. Anyone who suspects an infested ash tree in a county not known to have EAB is urged to contact the Iowa EAB Team.  

The adult beetle is metallic green in color and measures approximately one-half inch long and can be noticed during the summer months. The larvae burrow through the inner layer of bark, eating away at the vascular tissue, which supplies nutrients to the tree. Starved trees usually die within two to four years.

EAB-infested ash trees display canopy dieback beginning at the top of the tree and progressing downwards, S-shaped feeding galleries under dead or splitting bark, D-shaped exit holes, water sprouts (along the trunk and main branches), and increased bark damage by woodpeckers.

If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, the treatment window for protecting an ash tree begins very soon. Soil treatments should be made from mid-April to mid-May. Basal trunk sprays should be applied mid-May to mid-June. Trunk injections begin once the tree has a full canopy. Full details are available in Iowa State University Extension and Outreach publication PM2084, https://store.extension.iastate.edu/product/13114.

A federal quarantine, enforced by the U.S. Department of Agriculture, remains in effect and restricts the movement of all hardwood firewood and ash articles out of Iowa into non-quarantined areas of other states. To help reduce the potential for people to unknowingly transport EAB and other destructive tree-killing pests, Iowans are strongly encouraged to use locally sourced firewood.

Additional information, maps and photos of EAB are available at www.IowaTreePests.com.

About the Authors: 

Julie Sparks

Iowa Department of Natural Resources