Hinsdale trees get beetle vaccines
Hinsdale Forester John Finnell counts the rings in the stump of a green ash on Garfield Avenue that was cut down because it was infested with emerald ash borer. | Kimberly Fornek—Sun-Times Media
Updated: October 7, 2012 6:24AM
HINSDALE — As vaccines have reduced the danger of infectious diseases in humans, insecticides are being injected into trees to combat the spread of the emerald ash borer and Dutch elm disease.
Hinsdale has spent $107,000 so far this year on root and trunk treatments for the two organisms that threaten the life of the trees they infect.
Of about19,500 trees in Hinsdale, about 1,500 are ash.
Basically, all varieties of ash are susceptible to the emerald ash borer. Since February 2011, when the emerald ash borer was confirmed in Hinsdale, 46 ash trees infested with the insect have been removed from public property because they were damaged beyond the point of surviving, Hinsdale Forester John Finnell said.
After the beetles lay their eggs on the tree trunks, the larvae hatch and bore through the bark. There they feed on the tree’s nutrients and damage the tissue by which water and nutrients are carried throughout the tree. It may be three to five years after the larvae infest the tree, before the tree shows signs of deterioration.
Hinsdale hired Winkler’s Tree Service to treat 392 ash trees throughout the village with the insecticide, Xytect, between April and June, at a cost of about $8,700. Xytect is injected in the ground around the tree and drawn up through the tree’s root system.
The village opted for a more expensive treatment for certain ash trees due to their large size and canopy. Nels Johnson Tree Experts Inc treated 27 ash trees that line Garfield Avenue between 55th and 59th streets in May with the pesticide Tree-age. The treatment cost $7,360 and is expected to last for two years.
The trees, which already showed signs of ash borer infestation, were chosen because they “create an impressive streetscape,” the village did not want to lose, Finnell said. Their trunks are 2 to 3 feet in diameter and Finnell estimates they are about 60 years old.
Workers drilled holes about the diameter of a pencil into the trunk of the ash trees, around the circumference, 15 inches or so above the ground. Ten holes, for example, were drilled into a green ash whose trunk was 2.5-feet in diameter.
A hose encircling the trunk delivered the chemical simultaneously into all the holes, Finnell said.
“We’ll know in the next two or three years,” Finnell said. “If the tree dies, we’ll know it wasn’t effective.”