Des Moines, Iowa — Emerald Ash Borer is an Asian insect that kills ash trees and has now been confirmed in all but three of the 99 counties in Iowa.
The Iowa Department of Agriculture and Land Stewardship Communication Director, Don McDowell tells KIWA that Osceola County was one of six counties that had no confirmation for this insect. Today, January 19th, the department has confirmed that 96 counties now have an infestation. He says the insect sample that was sent to them was collected from Melvin. They also confirmed infestations in Monona County and Woodbury County at the same time.
According to McDowell, these insects are a significant threat to ash trees that are native to Iowa and once a tree is infected, usually it will take two to four years for that tree to die. He says it takes this long because the larvae feed on the inner side of the bark.
McDowell tells us that indications of an infestation may include canopy thinning, leafy sprouts shooting from the trunk or main branches, bark splitting, and woodpecker damage. Other things that may be noticed are “s”-shaped galleries under the bark and 1/8-inch D-shaped exit holes.
He says adult beetles can bring larvae from tree to tree when they fly away, but another way to spread the infestations is through people. An example is when people move materials, such as firewood. He says it is better to use locally-sourced firewood.
McDowell says there are options to make sure you don’t get an infestation. One way is to use preventive insecticide on healthy ash trees. The best time to use the insecticides, according to McDowell, is in the spring between mid-April and mid-May.
The three counties that have not yet reported an infestation are Plymouth, Emmet, and Palo Alto counties.
For more information on Emerald Ash Borer treatments visit the Iowa State University Extension and Outreach website at https://store.extension.iastate.edu/product/13114.
