The emerald ash borer is devastating ash trees in the area. We meet some researchers who are trying to understand the tiny green bug well enough to find an ash tree that can co-exist with this pervasive pest on Chicago Tonight at 7:00 pm.
If you have a tree that's infested with EAB, Andi Dierich, Forest Pest Outreach Coordinator at The Morton Arboretum, recommends calling a professional to have the tree properly assessed.
“Treatments are effective but you can only apply them, and have success with them, to a tree that has healthy tissue that can uptake the chemical,” said Dierich. “If a tree is too far gone, then it won’t have phloem tissue, which transports water and nutrients up and down the tree. If you don’t have that tissue, you can’t uptake the chemical.”
The chemicals essentially paralyze the central nervous system of the EAB, which kills it.
Dierich says the treatment comes in liquid form and can be applied as a soil drench around the base of the tree, or via trunk injections by a professional.
Scott Jamieson, certified arborist and vice president of Bartlett Tree Experts, says soil drenching is good to use when the level of the beetle is low, and is used as a preventive measure.
“When the beetle population gets high, soil drenching is not as effective as injecting,” he said.
TREE-äge is the material of choice typically injected into a tree. The treatment lasts for two years, which means it needs to be re-applied or it risks EAB infestation once the two years are up.
A new study from Michigan State found that annual treatment of 20 percent of ash trees protected 99 percent of the entire tree population after 10 years.
Jamieson says that the new study is causing a shift in some perceptions. He says suburbs like Naperville, Gurnee and Arlington Heights are using treatment by injecting infected trees with the TREE-äge chemical.
Jamieson says by doing so you are not only killing the larvae in the immature stages of development but also affecting the adult beetles.
“The adults come and nibble on the leaves and take in the chemical, so they are also dying. It short circuits their reproductive system and hinders their ability to fly around and ingest other trees,” he said.
While the new research sounds promising and cost-effective in that you only need to treat a portion of trees, Dierich says to keep in mind that this is not a one-time fix.
“You have to continue to use this chemical [every two years.] If you stop, the population of EAB is going to rebuild and you will see a high mortality rate for the trees,” she said.
As far as the cost of treatment, Jamieson says the average ash tree costs about $100 to treat, depending on the diameter of the tree. He says the price can range from $6 an inch to $12 an inch. And the treatment can only be administered by a professional arborist. Jamieson says to be sure to contact a certified arborist and a company that is accredited by the Tree Care Industry Association.
Both Dierich and Jamieson stress that once a tree is heavily infested and the tissue is damaged, treatment is no longer an option.
“If a tree is 40 to 50 percent infested, if there’s dieback in the crown or the tree looks weak and thin, if the plumbing system is damaged, the treatment is not as effective,” said Jamieson. “You have to inspect the tree before you make a prescription.”
Learn more about EAB by visiting the links below.