Sacrificing trees, importing wasps, all to fight the Emerald Ash Borer
Onondaga County is getting a new alert against the Emerald Ash Borer.
On Monday, crews were going to strategic spots around the county and girdling trees, cutting a ring of bark off them, so the tree will be an early warning system against the expected insect invasion. David Coburn, Onondaga County's Environmental Director, explains that the damaged tree then sends out a distress signal, that scientists hope will attract any invading insects to it, instead of to healthier trees. It's the latest effort in the county's plan to fight the expected invasion.
The Emerald Ash Borer is a bright metallic green insect, about a half inch long, invading from China. Its boring destroys ash wood, commercially valuable lumber, and the tree that many communities chose to replace diseased Dutch Elms in the mid-1900s.
Onondaga County is also in the process of counting its ash trees. Roy Widrig, who works for the Onondaga County Soil and Water District, is doing the census. He's checked all county parks, and areas around county-owned 911 transmission towers, and highway rights-of way, and is now working through town properties. So far, 26-thousand trees have been put into a computerized locator grid, 'targeted' because if they die and fall, they'd threaten roadways, wires or park-goers.
The City of Syracuse is also tackling ash tree concerns. City Arborist Steven Harris has a city response plan which includes cutting down small (less than 8" diameter) less-than-healthy trees, and replacing them with other types of trees. They've done 350 already this year, and in many cases replace with more than one new tree.
At SUNY ESF, researchers are looking at other ways to beat the Ash Borer. Forest Entomologist Dr. Melissa Fierke says the insect cannot fly far on its own, but travels with human help, mostly through infested lumber and firewood, moved around by campers. (NY has a 50 mile radius limit on where you can take firewood). She's also following development of more effective insecticides, which can be pumped into trees once they're infested.
One of Fierke's graduate students is monitoring another strategy: the Emerald Ash Borer had natural predators in its homeland, so now we're looking to establish them here, as well. Mike Parisio will spend the summer monitoring small parasitic wasps, being colonized in a downstate area where the borer is already established. The wasps, and two other small insect species, lay their eggs in the Ash Borer and ultimately kill that insect. Nature fighting nature, but there are concerns: that the predator insects can establish here, and that they don't become a bad invasive species in themselves.
When they cut down the 'sentinel trees in the fall, they'll check for the squiggly channels the borers cut into wood. If they find the evidence, says Environmental Director Coburn, efforts to fight the insect can be concentrated in that area. There will be 20 'sentinel trees,' around the county, in strategic places like near campgrounds, parks and places where timber and wood products move in and out regularly.
Another concern with this infestation, is that the public doesn't understand the impact this insect could have, so the girdled trees are being tagged with bright yellow information markers. On the tags' backs, a phone number, (315) 424-9485, to Onondaga County's Cornell Cooperative Extension, which has more information on the Emerald Ash Borer.