The decision to treat or not is based on the value of the tree in the landscape versus what you are willing to spend on a regular basis to save the tree. If you have several trees in your landscape, decide if you want to keep all of them or just a few key trees.
The problem is that you have to treat either yearly or every other year, depending upon which chemical is used. Currently there is no cure for EAB; you have to treat the tree in order to prevent EAB from killing it.
Therefore, if the cost to treat the tree is more than you are willing to spend, take the tree down before it dies. Once an ash tree dies, the wood is very brittle and the cost to remove increases significantly.
Control products last from one to two years depending on what is used. Therefore, treatment will have to be ongoing in order to save your trees.
Homeowners can treat by using a product that contains the active ingredient imidacloprid. Research has found imidacloprid to be one of the most effective in killing the most number of beetles. You mix this with water and pour around the base of the tree. Follow label instructions.
This is applied in midfall or in mid- to late spring. It is a systemic chemical that has to be absorbed by the roots and taken up into the tree so it takes some time to get into the tree. It kills the larvae that feed under the bark.
EAB is an insect that has the potential to kill all ash trees and has been found in almost two-thirds of Ohio’s counties. I suspect it’s in just about all counties, but it just hasn’t been discovered. It was identified in Ohio in 2003 and has quickly moved through the state — not by natural means, but by people.
You might have noticed billboards or television advertisements asking you not to move firewood. This is a campaign to prevent spread throughout Ohio. EAB is easily moved around the state in firewood. Therefore, if you are going camping, buy your wood near the campsite.
The decision about what to do with your ash trees is not an easy one. No one likes to take down healthy trees. However, this is being proactive. Plant a tree in place of the removed tree and begin developing shade for the future.
Just realize that if you are going to treat these trees, it’s not a one-time deal.
Pam Corle-Bennett is an Ohio State University Extension horticulture educator and the state Master Gardener volunteer coordinator.
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