EAB--Does Drenching Work on Big Trees?

What's the biggest ash that can be effectively drenched? (pick the closest size)

  • 10"

    Votes: 0 0.0%
  • 15"

    Votes: 0 0.0%
  • 20"

    Votes: 1 25.0%
  • Drenching is less reliable--inject them all!

    Votes: 2 50.0%
  • Any size can be managed by drenching.

    Votes: 1 25.0%

  • Total voters
    4

guymayor

Well-Known Member
Location
East US, Earth
We don't have a lot of ash but the green bug has arrived nonetheless. From what I read and hear, drenching works on smaller trees but larger trees have to be injected for effective control.

Is this true? Why or why not? What diameter is the threshold? I have a few big ash trees under my management, and I Hate to drill if I don't need to.
 

JD3000

Most well-known member
Location
Columbus
Answered this over at AS earlier but drenching works well under 15"-20" or so. Inject larger ones after that, I used the highest label rate and suggest 3 years if the tree is healthy. When insect pressure heats up, 2 years may be best but I bet 3 would still work well.
 

ATH

Well-Known Member
Location
Ohio
The second biggest ash I have been treating is currently 44" DBH. Started treatment in 2009 - they didn't want to spend extra for injection and this was pretty early in the cycle. Have pruned it once to take out a few dead limbs, but nothing major. This tree had a large dead area of bark (approx 2' wide x 3'+ high) at the base - likely physical damage during construction in late 90s. The same property has a 24" tree that has not had any significant dead limbs.

Another property has a 25" tree that they treated themselves for a few years starting in '08. Somebody injected it in 2010 with TREE-äge. I have been doing imidacloprid since 2015. Had to prune a "fair" amount of dead out, but the tree is not disfigured with what they lost.

My neighbor has a 25.5" tree that we have been treating with only imidacloprid since 2009 and it is in great shape.

Yet another property: 19", 23", 25". Started treating in 2009. New owners didn't treat after 2012. Another new owner has them now. There is some dead I them, but surprisingly too bad. They are back on the schedule starting this year.

I haven't lost a big one (or small one) that we started early. I do think the TREE-äge trees look better (treated every other year...or those who wanted to be even more aggressive were also treated with soil applied imidacloprid every year). This is a very heavy ash area...some woodlands I worked with were 75% ash. Most woodlands had at least 20% ash. So there was plenty of pressure.

What would I do if I started all over again? Though the TREE-äge trees look better, I don't love violating wall 4 every other year right at the worst spot to do so...but it works so well. It is not that much more expensive since it is every other year. I like doing the soil drenched better. Very fast. I'd still offer both, but probably push imidacloprid only a little harder - especially on very healthy trees.
 
Last edited:

ATH

Well-Known Member
Location
Ohio
PS: I should also add, that most of my "drenching" is done using this: https://mkrittenhouse.com/us/rootfeeder-soil-injector-with-or-without-flow-meter

PG-753_9.jpg


HUGE time saver. I figure out how much I need for the day, and mix it in the sprayer tank such that trees over 15" dbh get 0.5 liter per inch and those under 15" get a quarter liter per inch applied through several sites right at the base of the tree.

When I am not using this, I trowel around the base of the tree to make a trench about 2-3" wide and 2-3" deep and mix the appropriate amount for that individual tree in a gallon of water and pour it slowly walking around the tree 2-3 times. Not bad when I am only doing a few trees and don't want to drive the truck with the sprayer. Or, for example, I was treating some Rhizosphaera and EAB in the same town about an hour from here. I had the sprayer set up with fungicide, so I just did the individual trees with the "drench" instead of having to switch out products/rinse the tank.
 

JD3000

Most well-known member
Location
Columbus
I should add that we started in 04 treating here because we were an earlier outbreak. Big trees lasted a bit at the 0.2 rate but eventually succombed. By the time the label changed for most formulations we had moved on to em ben.
 

JD3000

Most well-known member
Location
Columbus
@ATH what rate are you tank mixing Imid in water? Follow-up question, how much is too much per 100 GL? It's so poorly soluble that I wonder if the average system has enough agitation for anything much over 1 oz per GL
 

ATH

Well-Known Member
Location
Ohio
I use the 2F formulation .2 oz per inch for the small trees and .4 oz per inch for the big ones. That makes it about 300 oz per 100. I've never had a thick residual in the tank at the end of a day so it seems to stay in suspension.

Before they changed the label it was pointed out (by somebody from ODA) that the labeled rate was "per application" not per year (but there ARE maximums per acre per year...). I asked what constituted a "separate application." They shrugged their shoulders and said they didn't know (I took it that was the whole point)...maybe the next day??? Given that vaguery, there MAY have been some trees that were given a separate application in rather close proximity on the timeline :whistle: A few got a fall and spring treatment - if they called me in the fall, i treated then and again in the spring to get them on schedule. That probably helped the bigger trees.

First call in the middle of summer when it was first hitting hard got dinotefuran...otherwise I couldn't justify the cost of that when imidacloprid works just as well. If you were going over your per acre limits, that would be a good next choice. We did that treating HWA for the first round when it was discovered at Cantwell Cliffs. From there they staggered imidacloprid because they are getting several years out of it for that pest.
 
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guymayor

Well-Known Member
Location
East US, Earth
ok so one guy sez 20" is the threshold, and the other guy sez there is no threshold.

No worries on a per acre basis; the trees are scattered.

Most of the drenching I do is with Paclo and I do the trowel/trench thing but start drenching the trunk at waist high and let it run down.

Do you buy local or get the imidacloprid online?
 

JD3000

Most well-known member
Location
Columbus
Local distributors that I've known forever. Price of Imid has gone up a bit, something to do with Chinese manufacturing I believe but could be wrong.

How bout 3 years on an injection then Imid the 4th? Buys the tree more time to lay down new wood at the flare? Perhaps a winning combo... Also, I would want the product in the leaves by the time adults are feeding so time apps accordingly. Imid is slow to move into the tree in heavier soil types or those with more OM. This really does a number on the population before a few sneak through to lay eggs. Less larval feeding the better.
 
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ATH

Well-Known Member
Location
Ohio
The research that I have seen from OSU and MSU agrees with @JD3000 but a lot of that is based on the lower rate before the label allowed for doubling the amount (based on research that came out of the same...). My reply was based on a relatively few trees. I don't have any controlled replicated studies to say I am correct - but I haven't lost any big ones we started early.

I'm not convinced on 3 full years out of TREE-age when the trees are under very heavy pressure... Maybe TREE-age in year one. Imidacloprid in years 3 and 4, then another TREE-age in year 5 if you wanted to get some benefit from both. The population may build a little in years 3 and 4 if you are killing fewer insects, but not likely enough to cause significant damage.

Not sure I'd spray imidacloprid on the bark like that. I'd worry too much will stay there and not be absorbed in. Yes...that is a good plan with dinotefuran as it will be absorbed through the bark as it is much more water soluble.

Finally, to echo the comment on timing: It is pretty late in the year to be doing just imidacloprid. I'd drop imidacloprid for dinotefuran as a summer treatment, then imidacloprid for 2019. However, I am in full swing doing TREE-age, as it goes in much better when the leaves are fully developed and that has just been in the last 2 weeks up here.

I buy online - Midwest Arborist Supplies mostly. Maybe TreeStuff if I am getting something else from them at the same time. I bought locally once, but they only had 75WSB which is harder to do precise dosing.
 

JD3000

Most well-known member
Location
Columbus
Agreed on treatments for when the heavy pressure when that infestation really starts to get cooking. Hit em hard and often.
 

ATH

Well-Known Member
Location
Ohio
Bucket??? I use an old gallon-sized Gatorade jug. Easy to seal the lid to shake it up and mix it well!
 

ATH

Well-Known Member
Location
Ohio
Is your bucked labeled? I did write "DO NOT DRINK" all of the lid and side of the container. I think that makes it official:baba:
 

JD3000

Most well-known member
Location
Columbus
I'm not supposed to drink from my graduated official insecticide applying bug killing bucket?

Might explain this headache and muscle spasms...
 

ATH

Well-Known Member
Location
Ohio
If you triple rinsed it first...

(of course, with only 3 rinses after using imidacloprid, there is probably still a lot of white stuff left in there)
 

Nish

Well-Known Member
Location
North Carolina
Do you buy local or get the imidacloprid online?

I've been getting most herbicides, and some insecticides, from Keystone Pest. Usually their labels match up well. (1 gal of Merit 2F equivalent is $56.95.)

Here's a question. I could buy a 10 pounds of 97% acephate from Keystone Pest for $85, or 10 ounces of 97% acephate for $59 from Rainbow Treecare, with the difference that the latter ("Lepitect") is labeled for soil drenching for tree pests. If I want to soil drench some big willow oaks for oakworm, must I pay for the Lepitect? On pain of what?
 
Last edited:

ATH

Well-Known Member
Location
Ohio
"The label is the law". As tempting as that price difference is I wouldn't use a product commercially in a way the manufacturer or distributor hasn't recommended.
 

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