DES MOINES – A new detection of an invasive pest has been positively identified after a larva sample was collected from a city-owned tree in Grinnell on June 16, 2015. This brings the total of confirmed infested counties to twenty-five since emerald ash borer (EAB) was first discovered in Iowa in 2010. This small, metallic-green beetle native to Asia kills ash tree species.
“This finding marks the seventh county in 2015 where EAB has been detected said Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB and gypsy moth coordinator. “As the summer wears on and people are more observant of their ash trees, it is inevitable that more counties will be added to the list.”
The City of Grinnell Public Services has been proactively planning for the arrival of EAB, prioritizing the removal of ash trees in poorest condition first. Along with removing declining ash trees, the city will be incorporating replacement trees and preventative treatment for select trees. City of Grinnell has approximately 400 city-owned ash trees.
A statewide quarantine, issued in February 2014, 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.
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.
The Iowa EAB Team strongly cautions Iowans not to transport firewood across county or state lines, since the movement of firewood throughout Iowa or to other states poses the greatest threat to quickly spread EAB and other plant pests. Most EAB infestations in the United States have
been started by people unknowingly moving infested firewood, nursery plants or sawmill logs. The adult beetle also can fly short distances, approximately 2 to 5 miles.
At this calendar date, the treatment window for soil-applied preventive treatment measures (soil injection, or soil drench, or granular application) has ended. Basal trunk sprays with dinotefuran can be applied until mid-June and are most effective for trees less than 18” dbh – the diameter of the tree’s trunk at breast height, 4 ½ feet above the ground. Trunk injection remains a viable EAB management option, as this method can be done when the tree has a full canopy of leaves (now through 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.
To learn more about EAB and other pests that are threatening Iowa’s tree population, please visit www.IowaTreePests.com.