Test results show insecticides kill ash borers' larvae in trees

EAST LANSING, Mich. (AP) -- Insecticides have proved effective in killing 45 to 96 percent of the larvae of ash borers, which have been killing ash trees in Michigan and elsewhere.
The insectides were tested at several sites this summer, said Deborah McCullough, a forest entomologist at Michigan State University.
The latest results were presented at the second annual international emerald ash borer science panel meeting, which drew researchers to Romulus earlier this month. They discussed their progress in learning more about the invasive wood-boring beetle.
The ash borer has killed more than 8 million ash trees in Michigan and also has infested trees in Ohio, Indiana, Virginia, Maryland and Ontario.
"Insecticide results look very promising," McCullough said. "It makes me feel much more confident that we can successfully treat trees and keep them going over the long term."
Treatments can cost $50 to $200 per tree per year, depending on the tree and method used.
Using insecticides for woodland trees "is not economically practical and, environmentally, you wouldn't want to do it," McCullough said.
There are an estimated 750 million ash trees in Michigan and the U.S. Department of Agriculture Forest Service puts the number of forest ash trees nationwide at 7.5 billion, with an economic value of $282 billion.