DES MOINES – The emerald ash borer (EAB), a destructive and invasive insect of ash trees has been discovered in central rural Montgomery County. Iowa’s growing number of counties with confirmed detection has now reached twenty-seven. Native to Asia, EAB has spread to 25 states since first being identified in Michigan back in 2002. This exotic pest is responsible for the death of tens of millions of ash trees.

EAB is a small, metallic-green beetle that is about ½ inch long. The larvae stage of this wood-boring insect tunnel under the bark of ash trees, disrupting the flow of water and nutrients, ultimately causing the tree to die. EAB infested ash trees include thinning or dying branches in the top of a tree, evidence of woodpecker activity, S-shaped feeding galleries under dead or splitting bark, D-shaped exit holes, and water sprouts (along the trunk and main branches).

“This find marks the westernmost site that we have found EAB in Iowa to date,” said Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB and gypsy moth coordinator. “This just reinforces the importance of limiting human-assisted firewood movement to reduce the spread of EAB and other injurious tree pests.”

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 Plant Health Inspection Service and the USDA Forest Service.

Since larvae of EAB can unknowingly be transported under the bark of a tree, the Iowa EAB Team strongly cautions Iowans not to transport firewood across county or state lines. The movement of firewood throughout Iowa or to other states poses the greatest threat to quickly spread EAB and other plant pests. A statewide quarantine remains in place, restricting the movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock out of Iowa into non-quarantined areas of other states.

At this calendar date, the treatment window for soil-applied preventive treatment measures (soil injection, soil drench, or granular application) and basal trunk sprays has ended. Trunk injection remains a viable EAB management option for the next two weeks, as this method can be done when the tree has a full canopy of leaves (now through the end of August), provided there is good ground moisture. If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, he or she should have landscape and tree service companies bid on work, review the bids, and treat during the recommended treatment time.

Please contact Iowa EAB Team members to have suspicious looking trees checked in counties not currently known to be infested. The State of Iowa will continue to track the movement of EAB on a county-by-county basis. Before a county can be officially recognized as infested, proof of a reproducing population is needed and an EAB must be collected and verified by USDA entomologists.