Since the emerald ash borer (EAB) was discovered in the United States, specifically near Detroit in the summer of 2002, it has killed more than 20 million ash trees in Michigan, Ohio and Indiana; caused regulatory agencies to enforce quarantines and fines to prevent the spread of infestation; and cost municipalities, property owners, nursery operators and forest industries tens of millions of dollars.
| CHECK FOR EAB |
Tree care operators can help clients determine if they have an emerald ash borer infestation by checking for the telltale signs, described on this FACT SHEET. |
In fact, fear of what the insect can do not only to an ash tree but to one’s pocket book has city officials scrambling. Counties within states where the EAB has been detected (Illinois, Michigan, Ohio, Indiana and Maryland) are realizing it’s more beneficial economically to come up with plans to proactively deal with the insect even if it hasn’t been discovered in their specific necks of the woods. The reason? “Once your county has been quarantined, you can’t move the ash wood or products out of the area and you have to chip and properly dispose of the chippings,” explains Dave Shetlar, associate professor, department of entomology, The Ohio State University, Columbus, Ohio. “Michigan and Toledo (Ohio) quarantine areas are finding that the cost of tree removal and legal disposal is running $300 to $600 per tree.”
As a result, “each community will have to decide what to do in order to minimize the economic impact of this pest,” Shetlar says.
For instance, in the heavily wooded suburb of Shaker Heights, Ohio, city officials plan to cut down all ash trees on public property before the beetle hits. In 2007, the city begins a five-year program to chop down more than 1,800 ash trees and replace them with other species. The cost, including replanting, is about $215,000. Strongsville, Ohio, which has about 750 ash trees in public areas, is also replacing them over a six year time period for the cost of about $300,000.
Though these plans sound extreme, it costs much less than waiting until the bug strikes, Shetlar says. “We have several communities here in the Columbus area that are also taking a preemptive strike by taking down ash street trees over a three- to five-year period,” he says. “This way they can spread the cost of tree removal and replacement over a longer period rather than waiting and facing the problem of having to take down all of the dead ash trees in a one- or two-year period. It’s not really a strategy for protecting themselves from EAB infestations but rather the massive costs associated with tree removals.”
According to the Ohio Department of Natural Resources, removing a live tree is cheaper than taking out a dead tree because the dead tree is more hazardous for a worker to climb. Currently, 21 counties in Ohio are fully or partially quarantined.
Emerald ash borer is an insect native of Asia where it can be found on several species of ash and is not considered a pest. Apparently, it was introduced by accident into Michigan via infested ash crating or pallets.
To stop the emerald ash borer’s spread, research is being conducted at universities to understand the beetle’s life cycle and find ways to detect new infestations and contain them more quickly.
Insecticides have shown potential for protecting trees from EAB, including soil-applied systemic insecticides, trunk-applied systemic insecticides, and protective cover sprays applied to the trunk, branches and, depending on the label, foliage, according to Shetlar and Dan Herms, associate professor, department of entomology, The Ohio State University, Columbus, Ohio.
“Some formulations can be purchased and applied by homeowners, while others can be applied only by professional applicators,” Herms and Shetlar said. “It is important to realize that success is not assured, and that trees will have to be treated each year. In many cases, it may be more cost effective to remove and replace the tree. Insecticide applications have effectively protected ash trees from EAB. However, in some research trials, trees have continued to decline from EAB attack despite being treated over successive years. In other trials, treatments have failed completely. The bottom line is that research on chemical control of EAB is still in its early stages, and we do not have enough experience to know if insecticide treatments will be effective over the long term.”
For more EAB information, visit http://ashalert.osu.edu and http://www.emeraldashborer.info.