A tiny beetle known for destroying ash trees is spreading in Iowa, state officials said Monday, and they predict infestations of the pest will pop up at a higher rate in 2015.
Larvae from emerald ash borer was found recently in Appanoose, Lucas, Mahaska, Marion and Monroe counties in the southern part of the state, according to a group that includes officials from the Iowa Department of Agriculture and Land Stewardship. The infestations are several years old, since it can take that long for an ash tree to show signs of decay from the beetle.
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The infestations include a region covered by hundreds of acres of woodland. It's the first time such an infestation has been linked to a rural area in the state since the beetle was first discovered in Iowa in 2010. Recent infestations have been confirmed in more urban areas.
Mike Kintner, emerald ash borer coordinator for the Iowa Department of Agriculture and Land Stewardship, called the newly discovered infestations "wide-ranging, with characteristic symptoms evident in woodland for mile after mile." A forest contractor out in Lucas County reported many dead ash trees, which led to the other discoveries.
The number of Iowa counties with confirmed cases of emerald ash borer has now increased to 18. Paul Tauke, a forester with the state Department of Natural Resources, said 2014 had a large jump, and he expects more in 2015.
"We're starting to see that baseline population where, now we're not just seeing symptoms and signs, but we're seeing our first tree mortality on a larger, geographic scale," he said. "I think the take-home message probably is, hold onto your seat belts because we're going to continue to see new EAB infestations and probably more counties at a more rapid rate."
Officials say Iowa landowners and community leaders should seek preventive treatment measures for ash trees in early spring. A statewide quarantine issued in February restricts the movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock out of Iowa into non-quarantined areas of other states.
Tracking the tiny insect is tricky because trees don't show immediate signs of distress.
"I think it's safe to say that we'll probably be finding more in the future, and probably safe to say that EAB is probably at lower levels, in other areas in Iowa. We just have not yet been able to detect it because the signs and symptoms aren't obvious yet," Tauke said.
Emerald ash borer is native to Asia and arrived in the United States around 2002. Larvae from the metallic green insect lives and feeds underneath the bark, cutting off the flow of water and nutrients to the tree. The beetle can kill an ash tree in two to four years.
Iowa was the 14th state in the U.S. to have a confirmed infestation of emerald ash borer. Twenty-four states are now dealing with the insect.