State officials confirmed this week a fourth county is infected with the emerald ash borer. A resident of Mechanicsville in Cedar County called to report a tree that didn’t look right. Department of Agriculture state entomologist, Robin Pruisner, says everyone in the state appears to be aware of the threat to ash trees. “We receive calls every day from landowners saying ‘I think I have a tree that may be infested can you come look at it.’ And we do the best we can to get out to all of those trees that they can tell us what those symptoms are and they appear to be in the ballpark of the right symptoms,” Pruisner says.
Pruisner believes the emerald ash borer is getting blamed for a lot of trees that are under stress but not infected. She says the back-and-forth pattern of drought and wet conditions has caused major stress to trees, and there are some native tree borers which take advantage of those trees. “And they also tunnel under the bark, they also have exit holes, though they don’t look exactly like the emerald ash borer,” Pruisner explains. “Because you see insect activity in your tree, that doesn’t necessarily mean it could be the emerald ash borer — it could be one of our usual insects that work on ash trees.”
While the emerald ash borer is spreading into new areas of the state, Pruisner says it is moving slowly and you’ve don’t have to go right out with the chainsaw and cut down your ash trees. “We still say that if you’ve got a healthy ash tree to just enjoy it. If you have an ash tree that’s already in decline — its got issues whatever it may be — then that’s when you might want to strongly consider maybe diversifying, putting something there in its place,” according to Pruisner.
There are some treatments to try and prevent the emerald ash borer. “Iowa State University does have insecticide recommendations for those who landowners who would like to treat their trees,” Pruisner says. She says the general guideline is you should only treat if your live within 15 miles of a known emerald ash borer infestation. And there are guidelines for the timing of when to treat the trees to get the best results.
Pruisner says fall is not the time when such treatments are done. Officials say the treatments can be costly and have not been effective in the long term at slowing down the spread of the emerald ash borer.