Survey crews are training for a time when the emerald ash borer finds its way to South Dakota trees. The exotic insect feeds on black, green or white ash. The trees have no defense against the beetle. State, local, and federal agencies are collaborating on a practice exercise in Sioux Falls.
State forester Gregory Josten says to claim South Dakota has escaped the emerald ash borer so far isn’t necessarily true.
"We don’t know for sure that it’s not here, but we have not found it here yet," Josten says.
The threat of an infestation prompts two dozen people to venture outside in a chilly April mist to sharpen their beetle-spotting skills. Officials use photos stuck to trees to test participants on finding and identifying emerald ash borers.
Josten says the insect is a serious problem, because it devours the insides of ash trees.
"It builds up a population to the point where there are enough tunnels under the bark that it basically consumes all of the tissue under the bark that moves nutrients, and eventually that tree dies," Josten says.
Josten says ash trees are native to South Dakota, so they grow naturally. He says they also make up about one third of trees in communities, because people like them. But Josten doesn’t recommend adding ash to the backyard.
"We want to diversify our species composition in our communities and across the state, and the best way to do that is to find different types of trees that grow here and plant those," Josten says. "But don’t plant ash trees anymore. We have a lot of them, and it would just be heart-wrenching to put in a tree now and, just as it gets large enough, find out that we’ve got an emerald ash borer infestation and lose that tree."
Treatments exist to save ash trees from the beetles, but Josten says applying them now before an invasion infuses unnecessary chemicals into the environment and wastes money.
Officials say people are major cause of the spread of emerald ash borers. Josten says people should avoid transporting firewood from one area to another, because it’s one quick way the beetles find new territory.
"It’s really a shame that we have this threat, but if we take actions, if we don’t move firewood, and we’re prepared and respond quickly to emerald ash borer when it is found here, we’ll be able to slow down the spread and hopefully be able to enjoy ash in our communities and across the state for a long time," Josten says.
Josten says the emerald ash borer could show up anywhere in South Dakota. The insect first appeared in the United States in the 1990s. Officials say the bugs have killed trees in 25 states so far including Minnesota and Iowa.