This time last year, Jefferson County was an island on the map of Missouri showing places where emerald ash borers have been discovered in the state. A state Department of Conservation press release issued at the end of 2018, explained that the isolation is no more.
The number of confirmed counties jumped from 42 to 59 last year, and the discovery in Jefferson County was announced last summer. I had written about our county’s island status in early August, and in typical journalism-jinx fashion, the state issued a notice in the middle of that month.
The state Department of Agriculture had placed specialized traps in areas of the county, and while checking those large, purple prism devices on July 2 last year, one emerald ash borer (EAB) was found in the trap at Morse Mil lPark near Hillsboro.
When Jefferson County appeared as a bull’s-eye on the map, I concluded that it was naive to believe that the invasive species wasn’t present here. Now that it has been confirmed, basically in the center of the county, it’s obvious you could find the pest in other places here, too.
“At this point, I don’t have any records of EAB from other parts of Jefferson County, although I imagine there are several locations where you could find the pest if you looked hard enough,” said Robbie Doerhoff, forest entomologist for the conservation department.
The trapped insect provides definitive proof, but in a way it means bad news, since trapping is not the quickest method for discovering the borers in an area.
“It can take at least five years for the population to build to the point where we can detect it using specialized insect traps,” Doerhoff said. “We really rely on public reports to help us find new EAB locations.”
The winter months are prime time to find one of the tell-tale signs of an emerald ash borer infestation called bark blonding. As woodpeckers remove the outer layer of the tree looking for insects just under the surface, the remnant light wood stands out as bright patches. Other evidence on the tree surface are s-like paths just under the bark and d-shaped exit holes created when the adult beetles emerge.
Emerald ash borers were first detected in Missouri in July 2008. The small, metallic green beetle is native to Asia, attacks all species of ash trees, and kills 99 percent of infected trees within three to four years.
Although the half-inch long, green adult beetle feeds on leaves of the ash tree, it actually does very little damage. However, in its larval stage, the insect kills ash trees by feeding on the water- and nutrient-conducting tissues just under the bark.
“Ash trees with bark blonding may not have EAB, but it is certainly worth reporting these trees for a closer look by MDC foresters,” Doerhoff said.
While the department is most interested in reports from counties that are yet to be confirmed for the pest, she said the public is always welcome to ask questions about emerald ash borers and potential treatments to protect ash trees.
Reports can be made by using the online form at eab.missouri.edu. For more information call the the state’s Forest Pest Hotline at 866-716-9974 or email forest.health@mdc.mo.gov.
The emerald ash borer was first discovered in the United States in 2002 near Detroit in southeast Michigan. It has since been confirmed in 35 states and five Canadian provinces. Its rapid spread is most frequently associated with transportation of firewood.
You can help slow the spread of invasive forest pests by using locally harvested firewood. Larva can emerge as adult insects up to two years after a tree has been cut. When firewood is moved from one location to another, you may be providing a free ride to an invasive species.
John J. Winkelman is community relations manager at Mercy Hospital Jefferson. If you have news for the Leader’s Outdoor News page, e-mail ogmjohnw@aol.com and you can follow John on Twitter at @johnjwink99.