(Des Moines)– Emerald ash borer has been confirmed in two more northwest Iowa counties. Iowa State University Extension and Outreach says the invasive pest was found in samples collected from ash trees in Spencer in Clay county and near Paullina, in O’Brien county. Officials with the USDA Animal and Plant Health Inspection Service confirmed the samples tested were emerald ash borer.
The adult beetles of the insect feed on ash leaves. Officials say that, in itself, causes very little damage. However, they say it’s the cumulative damage by larval feeding on the inner bark that eventually kills ash trees. Signs of infestation 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.
Preventive insecticide treatments are available to preserve and protect ash trees not already infected with EAB. Experts say mid-April to mid-May is the best time to treat for the pest.
