What poison for badly stressed pecan?

[Canyon Angler]

Hello, all,

Some might remember, last year during a tropical storm my ~40" DBH pecan tree (40'-50' tall) was struck by lightning. For photos, see:

http://www.arboristsite.com/showthread.php?t=36751

One large limb died as well as a smaller, lower, one, and large cracks developed in the bark (>1" wide in places) right down to the sapwood, and now some opportunistic insects seem to be taking an interest. On top of that, we're having a DRY summer.

What I plan to do is spray the trunk of the tree with insecticide to try to keep the bugs from making things worse. (I have written off any pecans it might produce this year - and it doesn't produce every year - so toxicity of any pecans is not a concern.)

My question is, what insecticide should I use? Right now, I have supplies of Sevin, Malathion and Dursban. Does anyone have any thoughts on which would be best? Should I use all three?

Thanks for any advice.

CA

 

[Dixie1]

dursban was banned back in 2000, but i believe you can still use what you have. http://archives.cnn.com/2000/HEALTH/06/08/dursban.ban.02/index.html

 

[Canyon Angler]

Thanks for all the great replies. I used chlorpyrifos and malathion. The bark is really cracking bad around about 60% of the circumference of the trunk, so maybe it'll be for naught but I've got my fingers crossed!

 

[jrparbor04]

wow,,,someone still has dursban,,,malathion is a good insecticide,,,sounds like you are just trying to keep the tree alive alittle longer,,,lightning strikes are of course,,,bad news to a tree,,,the nutrients struggle a bit to go from tip to roots and roots to tip,,,good luck with it

 

[Elmore]

Hmm...organochlorines & organophosphates

Dursban if you don't have Lindane.

 

[Kneejerk Bombas]

This is a hard question to answer.
Arborists have been trying forever to figure out what the best way to prevent decay advancement once there is a defect in a tree. They used to think painting the wound would slow decay, it doesn't. They've tried insecticides, fungicides, and other concoctions. None have shown any slowing of decay.
The other tactic is to try to increase growth to quickly close the wound back up. We've now found closing the wound does little to slow the decay inside that compartmentalized area.
Faster growth does add girth, but it also adds weight. This begs the question, is faster growth a good thing? We just don't know.

Your question was about insecticides. It's illegal to apply insecticides in a manner that is inconsistent with the label, and I'll add that it's stupid too. What specific insect do yo think is advancing the decay in your tree? You're too far north for termites, ants only dig in wood that's already rotten, borers like live wood, I guess I can't think of any insects that could be a problem.

When you apply insecticides, you kill beneficial insects too. You could very well cause greater stress for the tree.

You could have a good arborist come assess the tree for safety, to do some deadwood trimming, and perhaps do some reduction work (start a staged removal).

Here's a good site, with lots of pictures, to help you understand what happens when a tree is wounded:http://www.na.fs.fed.us/spfo/pubs/misc/treedecay/cover.htm

 

[Canyon Angler]

Thanks, Mike. I don't know what type of insects they are but there's "sawdust" accumulating between where the bark/cambium split away from the sapwood. Powder post beetles? Some kind of borers? Subterranean termites? (We've got plenty of them!) I dunno, but whatever they are, they can't be beneficial if they're making sawdust, I shouldn't think.

Unfortunately, I'm afraid the tree is toast, but I'm not going down without a fight!

 

[Kneejerk Bombas]

Find out what you are dealing with, then you can make an intelligent protocol for managing the problem.
Wood boring insects are very tricky to control; they live inside the wood, protected from insecticide sprays. You may need a systemic like Imidicloprid, but again, you need to know what you're controlling, and more importantly, that they are even a problem. Ants, for example, bore into dead wood and can leave sawdust, but their activity is considered beneficial to the tree.

 

[treeseer]

Along with managing the insects (and I use eucalyptus oil and other botanical repellents before stronger toxins), you should manage the tree, starting with the roots. Below is a protocol for managing lightning damage. See 4 and 5 at the end.

Lightning-Struck Tree Assessment and Mitigation.

When lightning strikes a tree, the owner will often assign an arborist to help determine the appropriate response. Depending on the tree and on the arborist, what they hear will range from “It’s going to die, so we should remove it”, to ”It looks okay for now, let’s wait and see.” Neither of these extremes adequately addresses the owner’s or the tree’s needs. Both neglect useful tree care techniques for assessing and mitigating lightning damage:

1. Bark inspection. Tap the bark with a mallet to determine whether it is detached from the wood. Measure the detached areas. Probe any cracks in the xylem with a thin instrument to determine the depth. If the damage to the lower trunk is not extensive, inspect the crown.
2. Consider the species’ relative tolerance to lightning strikes, based on its compartmentalization qualities, grain pattern, and genetic vigor.
3. Consider the individual specimen’s vitality, and its location relative to people and property. Assess the risk.

Present treatment options to the owner, providing a prognosis of recovery if the treatments move forward. If the client is an insurance company, the arborist is often asked to make a recommendation because the tree work is part of a claim. If the owner decides the risk is acceptable, these steps can be taken:

1. Reattach the bark if it is still moist inside. Thin bark may move enough if it is wrapped tightly for a few weeks. Thicker bark may be reattached with fasteners such as staples.
2. If the bark cannot be reattached, it should be trimmed—“traced”—back to the point where it is attached to the xylem, so there will be no hollow area as callus tissue grows over the wound. This applies to all the bark, from the top of the tree down to the buttress roots.
3. The exposed wood should be treated to repel insects. Reapply as needed
4. The soil around the roots, especially those that carried the current, should be aerated as needed and inoculated with beneficial microorganisms such as mycorrhizal fungi. Any mineral element that is lacking should also be applied
5. Mulch the root system 2-4” with organic material, and irrigate as needed.

 

[Kneejerk Bombas]

2. If the bark cannot be reattached, it should be trimmed—“traced”—back to the point where it is attached to the xylem, so there will be no hollow area as callus tissue grows over the wound. This applies to all the bark, from the top of the tree down to the buttress roots.

I assume you mean to use a razor knife or saw to cut away at the loose bark, and I further assume you do this as you inspect and search for bark that could possibly be reattached. Reattaching loose bark makes sense, but tracing right away seems like it would damage at least some of the bark that would otherwise survive.

There doesn't seem to be a strong reason to worry about loose bark at this point, or at any time for that matter. It will shed on it's own in time, and there won't be the extraneous damage to marginal cambium that would surely be damaged if you start cutting next to bark.
Tracing is a practice that should be considered harmful to a tree, and only acceptable when done in moderation, and with the understanding that it is cosmetic only. Tracing should only be done after the new roll of callus is easy to see so you know where to cut, and that cutting should take place out away from the edge of the wound, so some of the loose bark is left to shade that new roll of callus as it forms. This will slow the differentiation, and the doughnut hole of callus will close faster.

Just like with the washer countersinking during bracing, we want to minimize damage to trunk cambium.

3. The exposed wood should be treated to repel insects. Reapply as needed

In our area there are some special circumstances where there are insects that vector disease, we apply products that block the disease, like paint, but specifically what insects are you trying to repel?

 

[treeseer]

I assume you mean to use a razor knife or saw Tracing is a practice that should be considered harmful to a tree, and only acceptable when done in moderation, and with the understanding that it is cosmetic only. specifically what insects are you trying to repel?

Mike, as it was spelled out on page 8 here, in plain English http://www.tcia.org/PDFs/TCI_Mag_June_07.pdf
1. I use a hooked blade to avoid collateral damage.

2. Bark tracing, like the removal of all dead tissue, is not only cosmetic but therapeutic. If detached bark is not traced, callus tissue can grow along the bark instead of the wood, creating a cavity. I agree that on pecans in particular the bark is stiff and it is bad to enlarge wounds, so I have left detached bark at times. One near here got hit by a truck a few years ago and I compromised on that tracing task--I'll go out and get a pic today.

3. All damaging insects should be repelled

ok? opcorn:

 

[Kneejerk Bombas]

The concept that by removing loose bark you avoid a hollow area in the cambium, goes over my head. Could you explain that to me?

The other question I have is what insects, specifically, are damaging to trees? You're talking about ants, aren't you?
Seriously, you mentioned "unidentified borers", I have never heard of treating trees for unidentified insects, because it's difficult to come up with a control protocol and there may not really be a threat posed by the insects. All you're doing is starving the poor skink.

 

[Ekka]

Canyon Angler

How about some pics now?

Just give it some thought what the root system might be like, all things stem from the roots.

 

[treeseer]

The concept that by removing loose bark you avoid a hollow area in the cambium, goes over my head. Could you explain that to me?

OK. If the bark is detached, with the cambium, the cambium will grow along the detached bark instead of along the wood. The wood will remain separated from the cambium. The area between them will have air--a hollow. I've seen a doug fir that was hit 25 years before with callus several inches thick growing along bark, and wood rotting inside because there was a hollow.
What I said was "2. If the bark cannot be reattached, it should be trimmed—“traced”—back to the point where it is attached to the xylem, so there will be no hollow area as callus tissue grows over the wound."..."For reasons of discovery and assessment, removing bark that is too dry and discontinuous to be reattached seems like a necessary part of the assessment process. The tool used for bark removal should have a hooked blade, so with care the wood and the intact bark will not be needlessly damaged. Often bark is dislodged from the wood but still continuous, so a visual inspection is not enough. An auditory inspection is done by tapping the bark with a rubber hammer. A hollow sound indicates that air is resonating in the space created when the bark is detached from the wood.

The other question I have is what insects, specifically, are damaging to trees? You're talking about ants, aren't you?
Seriously, you mentioned "unidentified borers", I have never heard of treating trees for unidentified insects, because it's difficult to come up with a control protocol and there may not really be a threat posed by the insects. All you're doing is starving the poor skink.

When there is a lot of new exposed tissue, borers will be attracted. Specific ID usually comes first, except in the case of preventive treatment. We can't trust the skinks to be adequate control after that kind of damage.

 

[Kneejerk Bombas]

It seems to me a hole under the cambium is better than no cambium. Bark with living cambium attached should be reattached to the tree, not cut off!
You removing this bark is a perfect example of why tracing is so bad.

Even tugging on bark to see if it's properly attached and the cutting with the hooked knife is going to do a lot of collateral damage.

Controlling borers is tricky, there is attraction to trees that are under stress, but that attraction is not caused by open wounds, it's caused by the stress.
We know this because many of the Dutch Elm Disease and Oak Wilt studies involved counting (and identifying ) insects on wounds.
Borers tend to be attracted to trees under stress, lay eggs in crevices in the bark, and when the eggs hatch the little guys bore in through the bark. Painting the wound has no deterrent effect.
Adult borers can't bore, and larval borers can't fly.
It would be great if your theory held true. We could use Tree Tanglefoot on open wounds and trap all the adult borers before they lay eggs.

 

[Canyon Angler]

Thanks for the hearty discussion and debate, guys. I appreciate it.

Without getting into the merits vs the drawbacks of bark tracing, what tool would you guys suggest for tracing the bark on my pecan? The reason I ask is, the bark is probably close to an inch thick. There's no way I or even Arnold Schwarzenegger could cut it with a knife, if we didn't want to spend the next 2 years at it. So what else could I use? Would the tip of a chainsaw bar be OK?

Ekka, I've attached some pics taken today. I plan to remove the dead limbs before the year is out. The strike was during tropical storm Alberto in June 2006. It really did a number, didn't it?

Thank you for any and all advice, gentlemen.

Jeff

 

[Canyon Angler]

one more pic

attached below.

 

[Dixie1]

Along with managing the insects (and I use eucalyptus oil and other botanical repellents before stronger toxins), you should manage the tree, starting with the roots. Below is a protocol for managing lightning damage. See 4 and 5 at the end.

Lightning-Struck Tree Assessment and Mitigation.

When lightning strikes a tree, the owner will often assign an arborist to help determine the appropriate response. Depending on the tree and on the arborist, what they hear will range from “It’s going to die, so we should remove it”, to ”It looks okay for now, let’s wait and see.” Neither of these extremes adequately addresses the owner’s or the tree’s needs. Both neglect useful tree care techniques for assessing and mitigating lightning damage:

1. Bark inspection. Tap the bark with a mallet to determine whether it is detached from the wood. Measure the detached areas. Probe any cracks in the xylem with a thin instrument to determine the depth. If the damage to the lower trunk is not extensive, inspect the crown.
2. Consider the species’ relative tolerance to lightning strikes, based on its compartmentalization qualities, grain pattern, and genetic vigor.
3. Consider the individual specimen’s vitality, and its location relative to people and property. Assess the risk.

Present treatment options to the owner, providing a prognosis of recovery if the treatments move forward. If the client is an insurance company, the arborist is often asked to make a recommendation because the tree work is part of a claim. If the owner decides the risk is acceptable, these steps can be taken:

1. Reattach the bark if it is still moist inside. Thin bark may move enough if it is wrapped tightly for a few weeks. Thicker bark may be reattached with fasteners such as staples.
2. If the bark cannot be reattached, it should be trimmed—“traced”—back to the point where it is attached to the xylem, so there will be no hollow area as callus tissue grows over the wound. This applies to all the bark, from the top of the tree down to the buttress roots.
3. The exposed wood should be treated to repel insects. Reapply as needed
4. The soil around the roots, especially those that carried the current, should be aerated as needed and inoculated with beneficial microorganisms such as mycorrhizal fungi. Any mineral element that is lacking should also be applied
5. Mulch the root system 2-4” with organic material, and irrigate as needed.

specifically, what botanical oils are you using and what are they controlling? I am very interested as I would much prefer to try these before the heavy duty pesticides. Thanks!

 

[treeseer]

specifically, what botanical oils are you using and what are they controlling? I am very interested as I would much prefer to try these before the heavy duty pesticides. Thanks!

I like eucalypts oil and melaleuca oil. I applied euc oil annually to a white oak that had a 10" gash 70' up the trunk and it was totally closed in 4 years no borers.

On thick bark yes the tip of a chainsaw works IF you can control it. Otherwise hammer and chisel. Mike yes pulling on bark can extend injuries, and yes cutting off bark that cannot be reattached but has cambium is a very tough decision to make. I've erred on the side of "Do no harm" before and let it be, only cutting when the benefit clearly exceeds the cost, it's laborious and nerve-wracking to do it carefully.

i'll try making a video of the procedure; dunno how else to explain it.

 

[Ekka]

Over here we can buy aerosol eucalyptus oil, just shake and spray.

On a poinciana I worked on recently there was a large old wound where the bark was dead but lifted from the cambium, I carefully took it off and traced back to the callus wood which was growing. It was a bugfest under that piece of dead bark, sprayed it with euc oil and you should have seen the bugs go running.

Some of the beetles fell to the ground and hastily made up the trunk for the wound, when they got within a few inches of it they turned around and wandered off elsewhere ... most disgruntled I'd say.

Here's a pic of the wound, the cut was bad, left a stub and the limb is perhaps 10" dia. I advised the customer to spray euc oil regularly.