Serving O'Brien & Clay Counties
Serving O'Brien & Clay Counties
96 Iowa counties now reporting infestations
The adult beetles feed on ash leaves, causing very little damage. It is the cumulative damage by larval feeding (pictured) on the inner bark that eventually kills ash trees.
An invasive green beetle has made its way to another northwest Iowa county.
The Iowa Department of Agriculture and Land Stewardship on Jan. 19 confirmed that an infestation of the emerald ash borer (EAB) was discovered in Melvin. In addition to Osceola County, state officials also announced Monday the invasive pest was found in Monona and Woodbury counties.
Since its original detection in 2010, the invasive, ash tree-killing insect has now been confirmed in all but three of Iowa's 99 counties – Emmet, Palo Alto and Plymouth. The beetle last winter was confirmed to have made its way to O'Brien and Clay counties.
The beetle is the No. 1 threat to North American ash trees. Originally from Asia, EAB traveled across the ocean and was first discovered in Michigan in 2002. Experts believe the species hid in wood packing material or other shipping containers.
The adult beetles feed on ash leaves, causing very little damage. It is the cumulative damage by larval feeding on the inner bark that eventually kills ash trees. The feeding cuts off the tree's ability to transport water and nutrients, typically killing a tree within two to four years. According to the Iowa Department of Natural Resources, EAB is a significant threat to all ash species.
Indicators of an infestation may include canopy thinning, leafy sprouts shooting from the trunk or main branches, serpentine ("S"-shaped) galleries under the bark, bark splitting, woodpecker damage and 1/8-inch D-shaped exit holes.
While EAB can travel locally by natural means, long distance spread of this insect is attributed to people moving infested material, including firewood. People are reminded to use locally-sourced firewood where it will be burned to help limit the spread of EAB and other invasive pests.
The DNR encourages Iowans to decide a course of action for ash trees at risk of an EAB attack (within 15 miles of a known infestation). Landowners and managers can choose to wait and see what happens, remove declining ash trees and replace them with other species, or use preventive insecticide treatments to preserve and protect valuable and healthy ash trees.
Spring, from mid-April to mid-May, is the best time to treat for EAB. Insecticides are most effective when the ash tree is actively growing, and uptake is at its peak. Tree service companies can apply insecticide trunk injections through the summer if soil moisture is available.
The State of Iowa continues to track the spread of EAB on a county-by-county basis. Before a county can be declared positive, a life stage of the insect must be collected and confirmed. Anyone who suspects an infested ash tree in a county not currently known to be confirmed with EAB is encouraged to contact one of the following:
• Iowa Department of Agriculture and Land Stewardship, State Entomologist Office, 515-725-1470.
• Iowa State University Extension and Outreach, Entomology, 515-294-1101.
• Iowa Department of Natural Resources, 515-725-8200.
