MOUNT VERNON, Iowa (KCRG-TV9) - It’s working. That’s what Mount Vernon Horticulturalist Mike Wehde says about an ash tree treatment aimed at stopping the spread of the emerald ash borer.
For two years, Mount Vernon has been injecting city ash trees with a chemical called TREE-age that kills beetle larva. To date, 211 trees have received the treatment. Wehde said none have shown signs of infection.
"It's probably the best system right now," he said. "Pretty much a 97% kill ratio of the larva."
Iowa’s first confirmed case of the beetle was in 2010. Since then, it has spread to 31 counties, including Linn, mostly in the eastern half of the state. More than a third of the new locations have come in the last year, state agriculture officials said.
In February, the EAB was discovered in Johnson County by facilities workers at the University of Iowa. The workers noticed trees showing symptoms of an ash borer infestation.
Common evidence includes thinning or dying branches in the upper canopy S-shaped feeding galleries on decayed bark, and D-shaped exit holes.