Effects of repeat stem micr-injections?

Bermy

Acolyte of the short bar
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Ok, so I have started doing stem injection treatment for Elm leaf-beetle.
I'm using the 'Wedgle Direct Inject' system which only has a small hole that goes in as far as the the bark/wood interface.

Elm beetle will probably be around for many years to come, and I anticipate having to re-inject tree in the future. I'm hoping to get 2-3 years of protection from each cycle of injection...seems to be possible based on previous efforts by others.

SO what I'd like to discuss is, what do you think the long-term impact will be on repeatedly injecting a tree around its circumference probably 3 yrs. apart.
The initial injection sites are staggered vertically so there is not a horizontal 'zipper line', rather if there is any damage to tissue that it would be spread out and separated.
You can't use the same area for subsequent injections, so in two or three years, I'd be using the spaces left from this go around...and in three years from then, another area...and on and on.

I've seen trees cut down that had repeated attacks from string trimmers at their bases, years of small compartmentalized wounds, but plenty of sapwood between them...somewhat debilitated trees to be sure, but still functioning.

The trees I'm talking about are big, old established trees, still actively growing, but is there a risk of gradually causing any girdling effect? Of causing more harm than good, i.e, the cumulative physical effect of repeat micro-injections outweighing the effect of insect control?

My initial thought are that wall 4 would come into play, and next year there would be a layer of new sapwood over the injection site, and more layers in subsequent years...but how often could you introduce small 'defects' before they collectively became a problem...or is this just one of those impossible 'what if' scenarios!
 
I have wondered the same thing. I have cut down quite a few Maples and Oaks that were injected for chlorosis, there are typically long, vertical columns of discoloration. Can't say for sure what killed the tree but I had a feeling the injections may have been a contributor. Granted these were small diameter (10''-24'' range). I bet on a large Elm it wouldn't be too bad.
 
I've seen that same staining from infection sites. But having injected many trees annually or every second year with no noticeable effect (on the outside) it seems a lesser of 2 evils. We often raise the injection site as well if not treating for stem borers
 
Are you using Pointer? You could intermix your trunk injections with bark banding with Zylam liquid. It is also a neonicotinoid the same as Pointers ai so not the most perfect choice but it would further space the trunk injection intervals.

Trunk injections do damage tissue so their use needs to be weighed against that knowledge. It has been the subject of much study and it seems the general consensus is to use it only when it is the best choice. Bark banding is a good alternative. Do not overlook cultural practices that would increase the leaf beetles natural predators, they have a long list.
 
....I have cut down quite a few Maples and Oaks that were injected for chlorosis, there are typically long, vertical columns of discoloration. Can't say for sure what killed the tree ....

This is really a different problem. Injecting a tree for a perceived micro nutrient deficiency has a lot of down sides. It does not address or do anything to correct why the tree is showing these symptoms. Also, micro nutrients are called " micro " not because of their lower importance but because they are needed in such small quantities. They can become toxic at high concentrations. But also keep in mind the stained or discolored wood does not automatically equate to dysfunction.
I would say that those trees died because whatever the problems they were experiencing were not corrected.
 
Why not a non-invasive basal trunk spray insecticide Bermy?

They act systemically, particularly when mixed mixed with a surfactant like PentraBark.


Noninvasive Systemic Basal Trunk Sprays
Studies to date indicate that the effectiveness of dinotefuran basal trunk sprays are similar to soil applications of dinotefuran or imida- cloprid. MSU and OSU studies have evalu- ated residues in leaves from trees treated with the basal trunk spray. Results show that the dinotefuran effectively moved into the trees and was translocated to the canopy at rates similar to those of other trunk-injected insecticides, and faster than other soil- applied neonicotinoid products.

I'll be applying a fungicide mixed with PentraBark as a systemic basal trunk spray to try n fight off phytopthora ramorum or sudden oak death in a grouping of four large coastal live oaks here in a few days.

Jomo
 
Yep, I was going to mention safari as well. It's a bigger hammer than pointer but it's my understanding that it metabolizes much quicker.
 
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  • #9
Thanks guys,

I discussed trunk banding with the company that comes over from the mainland to do soil injection and he said for large elms its almost a waste of time. Either the larvae clump at the top of the band and drop down below it and continue, or crawl under the band in the deep fissures or just stay up in the tree and do their thing anyway!

Penetrating stem sprays are interesting and a possibility, but I would have to enter a whole extra arena of certification. Also lot of the trees are in paddocks where sheep graze, or are around dogs and children, residue could be an issue. I personally am really not keen to get into larger scale chemical handling and application than what I presently do, had enough of that in my days as a Landscaper.

At the moment I'm using Bayer Silvashield injectable, 200g/L. It is the only product licenced for injectable use in Australia, soil drenches and sprays have more alternatives, but quality has been known to be an issue.

At least the pest control company are doing further research, working on other methods than soil or stem injection with imidicloprid.

Love to continue the discussion....
 
Thanks guys,

I discussed trunk banding with the company that comes over from the mainland to do soil injection and he said for large elms its almost a waste of time. Either the larvae clump at the top of the band and drop down below it and continue, or crawl under the band in the deep fissures or just stay up in the tree and do their thing anyway!....Love to continue the discussion....

Trunk banding + Zylam = trunk spray + Safari. It is the terms used by the chemical companies. Dinotefuran, the active ingredient in both Safari and its generic and cheaper counterpart Zylam is a super systemic that is absorbed very quickly and translocates much faster than imidicloprid but has a shorter residual, 90 to 120 days which has benefits in some circumstances.
Trunk banding is a simple, low pressure, low volume application that can be done with a hand held or backpack sprayer. It is more simple and faster than injections and very effective. It is nothing like whole canopy spraying. Look into it and see what you think.
 
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  • #11
Thanks, I will indeed...I need a few more options with this whole leaf beetle thing going forward.
 
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