DES MOINES – Emerald ash borer (EAB) has been confirmed in Audubon and Guthrie counties for the first time. EAB larvae were collected from infested trees in rural Exira (Audubon County) and Casey (Guthrie County). The invasive, tree-killing pest has been found in 71 Iowa counties since 2010.
EAB is a small, metallic-green beetle that attacks and kills ash tree species. In its larval stage, EAB bores beneath the bark disrupting the movement of water and nutrients within the tree. Infested trees typically die within two to four years.
Ash trees infested with EAB might include canopy thinning, woodpecker damage, water sprouts from the trunk or main branches, serpentine (“S”-shaped) galleries under the bark, vertical bark splitting and 1/8-inch D-shaped exit holes.
“Woodpeckers like to eat EAB larvae beneath the bark of ash trees,” said Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB coordinator. “Despite it being winter, woodpecker damage is an indicator EAB may be lurking in a tree.”
The adult beetle can spread naturally by flying short distances to area host trees; however, the more threatening long-distance spread is by human-assisted movement. Beneath the bark, larvae can unknowingly be transported in infested wood products such as firewood. People are encouraged to use locally-sourced firewood where they are going to burn it.
The entire state of Iowa is under quarantine for EAB. A federal quarantine, enforced by the U.S. Department of Agriculture, prohibits the movement of regulated articles such as living and dead material from ash trees and all hardwood firewood out of Iowa into non-quarantined areas of other states.
At this calendar date, the window for all preventive treatments is closed. 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 this winter and begin treating in spring 2020 (early April to mid-May). More details pertaining to treatment are available in Iowa State University Extension and Outreach publication PM2084.To find a certified applicator in your area, download and follow the steps in PM3074.
The State of Iowa monitors the spread of EAB on a county-by-county basis. Anyone who suspects an infested ash tree in a new location is encouraged to contact one of the following:
Iowa Department of Agriculture & Land Stewardship, State Entomologist Office: 515-725-1470
Iowa Department of Natural Resources: 515-725-8453
Iowa State University Extension and Outreach, Entomology: 515-294-1101
To learn more about EAB and to view known locations in Iowa, please visit http://www.iowatreepests.com.