EAB in Ohio 2023

macrocarpa

macrocarpa

Branched out member
Location
Midwest
I was talking to one of the ODNR Foresters and he was saying he doesn’t think it’s necessary to treat ash trees anymore in Ohio because the EAB populations have moved on.

Without solid evidence, I’m not willing to take that risk for my customers valued ash trees.

But I do wonder if treeage injections are necessary at this point or can we get by with just soil injections?

Has anyone made this transition or given it much thought?

I know the consensus has been soil injections work for anything below 15” dbh, but I wonder if the insect pressure is low if that still applies?
 
I disagree with the consensus that soil injections don't work over 15" (I assume you mean above, not below?)

I think that is "old information". It is true that it didn't work with the labeled rates of imidacloprid when EAB first hit. However, Herms (and others) studied the products, found that doubling the rate works and that they were not finding significant elevated risk with those rates. They brought that data forward and the labels were changed to allow doubling the rate. We've had a handful of clients that only wanted soil treatments. Some cost. Some didn't like the idea of drilling a tree. The biggest tree I treat is 46" DBH - and had some other insect damage before EAB. We've been treating it since 2007 or 2008 and it is doing great... I know that is a sample of 1, but there are others we've only treated with imidacloprid soil injections. I do agree that emamectin benzoate is more effective. But that doesn't mean imidacloprid is ineffective.

OK...to the original question. No, EAB has not moved on. I find it in trees that are untreated. I find it in trees that were likely treated by the previous owner - new owner comes in and doesn't know they have an Ash tree. I've gotten calls from people who were treating and they quit - EAB showed back up.

Can we move from emamectin benzoate to imidacloprid? I think so. I've offered that to several clients and their reply has almost universally been "what we are doing is working, so we want to stay with that". I've also suggested moving to every 3rd year instead of every other year with emamectin benzoate and get the same reply.
 
ATH said:
I disagree with the consensus that soil injections don't work over 15" (I assume you mean above, not below?)

I think that is "old information". It is true that it didn't work with the labeled rates of imidacloprid when EAB first hit. However, Herms (and others) studied the products, found that doubling the rate works and that they were not finding significant elevated risk with those rates. They brought that data forward and the labels were changed to allow doubling the rate. We've had a handful of clients that only wanted soil treatments. Some cost. Some didn't like the idea of drilling a tree. The biggest tree I treat is 46" DBH - and had some other insect damage before EAB. We've been treating it since 2007 or 2008 and it is doing great... I know that is a sample of 1, but there are others we've only treated with imidacloprid soil injections. I do agree that emamectin benzoate is more effective. But that doesn't mean imidacloprid is ineffective.

OK...to the original question. No, EAB has not moved on. I find it in trees that are untreated. I find it in trees that were likely treated by the previous owner - new owner comes in and doesn't know they have an Ash tree. I've gotten calls from people who were treating and they quit - EAB showed back up.

Can we move from emamectin benzoate to imidacloprid? I think so. I've offered that to several clients and their reply has almost universally been "what we are doing is working, so we want to stay with that". I've also suggested moving to every 3rd year instead of every other year with emamectin benzoate and get the same reply.
Click to expand...
Thanks! I’m on the same page :-)
 
Following up here. Consulting on a municipal project. I was still on the tree injection mindset. The trees have never been treated and are on a historical site. It's an early infestation, with two larger trees showing 30% decline. With 15 trees to be treated, and cost always an issue with local gov projects, would imidacloprid soil injection be a good solution? Upper Midwest for reference
 
just ro be clear...soil injection right around base of the tree (same idea as soil drench). Early recommendations were for application to drip line like you'd fertilize...but right at the trunk was found to be more.effective.

As stated above, imidacloprid does a good job. But certainly less dieback when using both emamectin benzoate.

On trees with 30% loss, I'd want a first treatment with emamectin benzoate (this fall of possible), then imidacloprid starting next spring every year.
 
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