The final county in northwest Iowa has now had its first emerald ash borer confirmation.
The Iowa Department of Agriculture and Land Stewardship’s map had shown certain pockets of Northwest Iowa to be the only area of the state to escape the infestation so far. However, it confirmed Thursday that the invasive species has now been found in Osceola, Woodbury, and Monona counties.
Insect samples collected in Melvin were analyzed by federal inspectors and the results came back positive.
EAB kills a tree within two to four years of infestation by cutting off the tree’s ability to transport water and nutrients. Infected treets are considered hazardous because they become brittle and subject to falling down.
The first sign of the disease is typically a thinning canopy. Other tell-tale signs are “D” shaped exit holes, serpentine shaped channels under the bark, loose bark, and woodpecker damage.
Officials with the Agriculture department say Ash tree owners within 15 miles of Melvin should decide now whether to cut down the trees or try an insecticide treatment. They say the treatment is most effective from mid-April to mid-May.