Soil drench versus trunk injection?

[cody willard]

So are there any case studies/actual scientific research that anyone can cite that shows testing between soil drench and trunk injections for effectiveness? Mostly pertaining to borers.

The more I ponder soil drenching, especially in some of our sandy soil’s in Tulsa, the more I wonder about their effectiveness and what percentage of the product actually makes it into the tree?

When it comes to trunk injections, everybody likes to point out that your wounding a tree, however in my 12 years of dealing with trees I’ve seen very few cases of that being the fact. One thing with injections is I feel like it would mean almost 100% of the product would make it into the tree if done correctly. Less variables and more control.

There is a company in town that I refer all my PHC requests to, but I’ve noticed that they only perform soil drenching, and some of these trees have significant signs of borers that need immediate treatment.

I have pretty much stayed out of PHC completely, but I do a lot of soil remediation. I want to make sure that who I refer work to is doing the most optimum job for my clients trees. If not, then I might have to start offer and treatments in the house.

 

[Lignotuber]

There's definitely research out there if you Google it, i think there's varying results for most of these chemicals and application methods and chosing what to use depends on numerous factors including, relevant research on effectiveness, target pest, species of tree, environmental conditions, budget, potential impacts to not target wildlife, laws and regs, exposure etc. I do think a good PHC company should at least have the equipment and capabilities to do trunk injections though.

 

[ATH]

emeraldashborer.info is a good place to find a lot of that info.

http://www.emeraldashborer.info/documents/Multistate_EAB_Insecticide_Fact_Sheet.pdf

summarizes options.

Soil drenches are more variable based on timing (spring is better) and rate (use highest labeled rate).

I see little reason to inject imidacloprid for EAB. Soil treatments are equally effective and it needs to be retreated every year regardless. That is a slower and more costly process. We do know that drilling a tree is injuring the tree. I agree that most of the time trees compartmentalize that well...but it is still an injury and in the case of imidacloprid, I'd argue, unnecessary.

I do inject tree-age (R10 formulation is my go-to now). That is slightly more effective than imidacloprid and lasts at least 2, perhaps 3 years so injection (injury) frequency is cut back substantially.

Don't forget dinotefuran bark sprays. I don't do those often because of cost, but it does get into the quicker than imidacloprid soil drenches. There is some research into imidacloprid bark sprays as well. I think NY allows them under a special use permit for Hemlock Wooly Adelgid.

 

[ATH]

There's definitely research out there if you Google it, i think there's varying results for most of these chemicals and application methods and chosing what to use depends on numerous factors including, relevant research on effectiveness, target pest, species of tree, environmental conditions, budget, potential impacts to not target wildlife, laws and regs, exposure etc. I do think a good PHC company should at least have the equipment and capabilities to do trunk injections though.

Agreed. The more options available, the more targeted treatments can be to not only the pest, but the circumstances. For example, do they do soil drenches in sandy soil immediately adjacent to surface water? Might control the pest, but also presents a higher probability of off target impact.

 

[Lignotuber]

emeraldashborer.info is a good place to find a lot of that info.

http://www.emeraldashborer.info/documents/Multistate_EAB_Insecticide_Fact_Sheet.pdf

summarizes options.

Soil drenches are more variable based on timing (spring is better) and rate (use highest labeled rate).

I see little reason to inject imidacloprid for EAB. Soil treatments are equally effective and it needs to be retreated every year regardless. That is a slower and more costly process. We do know that drilling a tree is injuring the tree. I agree that most of the time trees compartmentalize that well...but it is still an injury and in the case of imidacloprid, I'd argue, unnecessary.

I do inject tree-age (R10 formulation is my go-to now). That is slightly more effective than imidacloprid and lasts at least 2, perhaps 3 years so injection (injury) frequency is cut back substantially.

Don't forget dinotefuran bark sprays. I don't do those often because of cost, but it does get into the quicker than imidacloprid soil drenches. There is some research into imidacloprid bark sprays as well. I think NY allows them under a special use permit for Hemlock Wooly Adelgid.

Agreed, regarding the 10% i did see some research from rainbow like a year ago that showed 4% emamectin benzoate being notably more effective than the 10% solutions. After that, i generally reserve 10% for trees with poor uptake like some pines and palms.

 

[Basswood]

Urban arboriculture had a peer reviewed paper reevaluating the efficacy of imidicloprid drenches for EAB. I don’t remember the details.

for one there’s less off target impact with injections. As well as longer residual and efficacy (2 years for EAB).

 

[ATH]

Urban arboriculture had a peer reviewed paper reevaluating the efficacy of imidicloprid drenches for EAB. I don’t remember the details.

for one there’s less off target impact with injections. As well as longer residual and efficacy (2 years for EAB).

2 years with imidacloprid? Or tree-age?

 

[Basswood]

2 years with imidacloprid? Or tree-age?

Sorry tree-age/Mectinite.

 

[Chris Winters]

At this point in EAB treatments, it should be known and standard practice to be using Emamectin. Its much more targeted to the pest itself and has a higher/longer efficacy.