OSKALOOSA — The Emerald Ash Borer is a small beetle that kills all species of ash tree and has made its way into Iowa.
A panel of experts spoke about the Emerald Ash Borer and ways to protect trees at two workshops Tuesday held at the Iowa State University Extension office in Oskaloosa. An afternoon workshop was held for people in “green” industries while an evening session was held for the general public.
The largest population of Emerald Ash Borer found in the state to date has been in Burlington, in Des Moines County. Researchers are still determining how serious the infestation is in Burlington, ISU Extension Entomologist Mark Shour said.
The closest the Emerald Ash Borer has been found to Mahaska County has been Jefferson County.
The Emerald Ash Borer is spread primarily through people transporting firewood from an infested area. Thus, counties bordering known infestation sites have been quarantined to help stop the spread of the borer. Thus, Keokuk County has been one of the quarantined counties.
The Emerald Ash Borer can fly from 1 ½ to 2 miles and up to 5 miles, the borer tends to stay in one area. After feeding and mating, a female Emerald Ash Borer will lay from 40 to 70 eggs on or under ash tree bark. The larvae feed on ash trees and they make serpentine galleries as they worm their way through wood, Shour said.
The galleries prevent nutrients from the roots reaching the upper parts of the tree. Numerous serpentine galleries will make the tree’s bark fall off the trunk, he said.
“It takes two to four years to kill a tree,” Shour said. “It depends on the size and health of the tree.”
The Emerald Ash Borer hits the top of an ash tree first and then works its way down. By the time the borer reaches the lower parts of the trunk, “the tree is toast,” Shour said.
Besides serpentine galleries, other symptoms of an Emerald Ash Borer infestation are the tops of ash trees dying out, large D-shaped exit holes in trees and woodpecker damage to a tree.
“All varieties of ash are attacked by the Emerald Ash Borer,” Shour said. It’s the odor of the ash tree that attracts the Emerald Ash Borer, he added.
Homeowners can help protect their ash trees by having them treated with chemicals called neonicotinoids. They can be injected into the tree, injected into the soil around the tree, drenched in the soil around the tree or sprayed onto the tree, Shour said. The chemicals should be applied every year in mid-April to mid-May. There is another chemical called “Tree-Age” that can be injected into the tree that is good for two years, he added.
Herald Editor Duane Nollen can be reached by email at firstname.lastname@example.org