By Dustin Vande Hoef
An invasive beetle that kills ash trees, the emerald ash borer, has been confirmed in Ringgold County, making it the 52nd county in Iowa where this highly destructive insect has been found.
The recent EAB infestation was discovered by a tree service that reported suspect ash trees to the Iowa Department of Agriculture and Land Stewardship. Insect larvae were collected from this rural site west of Tingley, and positively identified as EAB.
EAB-infested ash trees can include branch dieback in the upper crown, water sprouts along the trunk and main branches, vertical bark splits, D-shaped emergence holes, S-shaped tunneling under loose bark, as well as woodpecker damage. EAB is difficult to detect in newly-infested trees.
All ash tree species are susceptible to attack by EAB. The larval stage of this insect kills ash trees by tunneling under the bark and feeding on the part of the tree that moves water and nutrients throughout the tree.
“We are already up to 13 new counties confirmed with EAB this year,” said Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB and gypsy moth coordinator. “As we continue to track EAB’s spread across the state, people are encouraged to report suspect trees in counties that have not yet been declared positive.”
EAB is native to Asia and was first identified in the U.S. in 2002 and in Iowa in 2010 in Allamakee County. Much of the pests’ spread can be attributed to humans inadvertently transporting it to new areas under the bark of firewood, logs and tree debris.
At this calendar date, the treatment window for soil-applied preventive treatment measures (soil injection, soil drench or granular application) and basal bark sprays has ended. Trunk injections can be done now through the end of August if a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation. Good ground moisture is essential for systemic insecticide movement in a tree. Full details are available in Iowa State University Extension and Outreach publication PM2084.