COLUMBIA — Killer beetles are taking down thousands of ash trees in Missouri, and Columbia wants to be ready.
The emerald ash borer, an invasive beetle that attacks ash trees, was first identified in Missouri in Wayne County in 2008, and it has since been found in Kansas City and seven additional counties in southeast Missouri. The damage caused by these pests can mean thousands, if not millions, of dollars in expenses for municipalities.
Columbia city arborist Chad Herwald has asked the Columbia City Council to spend $13,500 in state and city funds to have an urban forestry consultant inventory ash trees on priority streets in Columbia and prepare an emerald ash borer readiness plan. The consultants will also be on the lookout for the pest, whose arrival time is hard to predict.
A key problem: The pest is difficult to detect early. Once it arrives, the ash borer is difficult to control and monitor and, without action, could kill all the ash trees in the city.
"By the time we find some, they have spread in a large area," Robert Lawrence, forest entomologist for the Missouri Department of Conservation, said. "But we can’t detect how large of an area. If we can’t detect that, we don’t have the ability to eradicate."
Unlike some other wood borers, the emerald ash borer isn’t picky.
"Usually if you keep the tree healthy, nature has its balance and insects won’t kill healthy trees," Angela Belden, Missouri Department of Conservation resource forester, said. "But this will kill all healthy trees of all ash species."
Lawrence said within the ash tree genus, there are several species. Emerald ash borers will attack them all.
"It is a severe pest that has the potential to eliminate a whole genus," Lawrence said.
The city of Chesterfield started preparing for "when and if it arrives" three years ago. Mindy Mohrman, Chesterfield city arborist and urban forester, said the focus of the plan is managing and reducing the number of ash trees.
Chesterfield does not allow the planting of any new ash trees and has reduced the population by about 10 percent, which in Chesterfield equates to about 1,000 trees. Mohrman said that each tree removal costs $500 to $700.
Mohrman estimated that had Chesterfield waited to act until the arrival of the emerald ash borer, it would have cost the city $3.3 million.
Lawrence said managing the impact, as Chesterfield is doing, is important for cities to consider. He said it is "just a matter of time" before the emerald ash borer arrives, so now is the time to figure out how to spread out the impact.
"EAB (the emerald ash borer) starts with a slow number of dead trees, and then all the sudden takes off with exponential growth," Lawrence said. "A huge number of dead trees at once is more than a city budget can handle. You need a measured response over time."
Belden agreed the pest is going to arrive, and that the impact will be costly.
"When EAB gets to Columbia, all the ash trees are going to die," Belden said. "It is going to be millions and millions of dollars to remove and replace these trees, and you need budget for that."
Herwald said the consulting firm will provide suggestions for the most economical way to deal with the pest including a management plan and suggestions for prevention.
The consultants have worked with cities in Wisconsin and Michigan, Herwald said. "They know what works and what doesn’t, and what trees are worthy of chemically treating and what trees are more or less likely to be attacked."
Belden said you have to decide how to handle a tree on a case-by-case basis.
"There are insecticides you can apply to a tree. It’s expensive and has to be done every year," Belden said. "If you’re looking at applying every year and doing it for 20 years, it might just be cheaper to replace the trees and grow something else."
Lawrence said that dealing with emerald ash borers for 20 years is a reasonable expectation.
"It is hard to predict here," Lawrence said. "In Michigan, it has been there for about 20 years and they are just now seeing it start to go down."
Residents should not act upon the threat until the pest has been identified within a 15-mile radius of their location, but they can play a role in the preparation process.
Lawrence recommends that landowners with ash trees learn what to look for in an infestation and to call the Missouri Department of Conservation if an outbreak is suspected.
In addition, because moved firewood is largely responsible for the spread of emerald ash borers, people are urged to burn firewood at its origin to prevent spreading of the pest.
The consulting costs would be funded by a $10,000 grant from the Missouri Department of Conservation along with $3,500 from the city.
Herwald said he expects the city council to decide whether to provide the funds by late September, and the tree inventory and readiness plan would be completed by February.
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