Bacterial Leaf Scorch

KyLimbwalker

Well-Known Member
Does anyone have any experience with Bacterial leaf scorch in oaks? I am able to recognize the disease, but have never treated for it. Specifically, I am wondering about:

1. The efficacy of Bacastat (Rainbow Tree care) or any other chemicals.

2. Cultural solutions, such as mulching or aeration (I know that none of these cure the disorder, but can anyone present even anecdotal reasons for increasing the vigor of affected trees?)

Any information would be appreciated.
 

treegazer

Member
Bacastat which is oxytetracylcine has been found to delay the onset of symptoms by up to 3 weeks. Dr. Hartman at UK has been studying the disease and potential controls for several years. I had the pleasure of assisting him in the trials he performed last year.

Since BLS takes advantage of stressed trees it makes sense to do everything possible to reduce or prevent stress on the tree.

Searching the AUF Journal for Bacterial Leaf Scorch will provide a lot of info to read.

When we have a client with a tree that does not have it and is susceptible we recommend aeration/soil decompaction, root crown excavation if needed, and sometimes paclobutrazol.

If the tree has it but not that extensive, we recommend all of the above and pruning out the diseased limbs and continued monitoring.

Some clients have opted to remove the tree and replace rather than spend the time and money on a tree that will eventually succomb(sp?)to BLS.

Hope this helped.
 

treegazer

Member
One draw back to the OTC treatments is it needs to be injected into the vascular system. Treatments need to be repeated annually.
The OTC uptake is VERY SLOW. Possibly over night.
If I remember correctly we treat in late May early June but I would need to verify that, I'm just going on recollection.
We follow the OTC with Stemix to help move the OTC into the canopy faster (theoretically) I don't know if this technique is scientifically proven.
 

PUClimber

Active Member
The bacastat is what the lab recommended for the bacterial leaf scorch I have a list of what to mix it at if you're interested.
 

KyLimbwalker

Well-Known Member
What about just doing the aeration and mulching? Any benefits? Do I have to do the injections? What is the marginal benefit, I guess, of the oxytetracycline over aeration?
 

treegazer

Member
Couple of questions first.
1) What kind of tree?
2)How big/old/established is the tree?
3) How much of the canopy is affected by BLS?
4) got a picture of the tree?

OTC will just delay the symptoms. The thought here is that the leaves stay on the tree for 3 weeks longer(approx.) and give the tree more time to store energy thus prolonging its life by a few years.(Delay the removal and costs). Whether this is economical is debatable because you would have treatment costs every year. Pruning costs every year or two to remove hazardous dead limbs. And you are wounding the tree repeatedly.

Aeration and mulching will relieve stress which overall is the best thing for the tree.

If you are going to do the OTC injection you should definitely do the aeration and mulching.

Paclobutrazol(PBZ) can help with drought stress and possibly the thicker cutical may discourage leaf hoppers from feeding. But PBZ does nothing to affect the BLS in the tree.

If the tree is not that severely hit with BLS you could prune out what is and do the aeration and mulch and monitor.

If the tree is loosing, lets say 30% or more of its branches the aeration and mulch probably won't do much good. Thinking that the tree is in decline and it will likely die in a few years no matter what you do.

All you can do is lay out all the options and let your client make the call. And give your opinion if asked.
 

Chum

New Member
The world's largest producer of wine grapes, Mogan David, has extensive experience in scorch.

Rather than subject the sensitive vines to to what the extension services recommend, they've pioneered a simple program that replaces burmuda-grass ground cover between the vines (burmuda hosts the insect vectors of Pierce's disease) with a legumous clover. Problems solved.

With our experience on oaks, this replacement therapy has the same results. Unfortunately, this region is bombarded with the advice of the extension offices (which is fiscally rewarded to promote the cultivation of burmuda grasses) - and thus Scorch is prevalent here (except on trees managed by us).
 

Cyrus1254

New Member
Oak wilt same here in SC with the extension being the number one voice heard and the public thinks they are the best and sometimes they dont have a clue what there doing.
 

Chum

New Member
Being that they were established to promote good local agriculture and their information comes only from the land-grant colleges, one would expect quality advocacy from them.

The problem is, big ag-business got to them first and not unlike NASA being hobbled in order to give us filtered climate information by the politique-in-charge, ag extension means only mainstream information that's not up to snuff with current science. The main reason oak wilt has become an epidemic instead of a locally problematic soil-borne pathogen - the Ag Service was in charge of it here (and many other states as well).
 

KyLimbwalker

Well-Known Member
[ QUOTE ]

1) What kind of tree?
2)How big/old/established is the tree?
3) How much of the canopy is affected by BLS?
4) got a picture of the tree?



[/ QUOTE ]

First of all, thankyou Stacy for your thorough responses. Good to see you the other day , too.

Here is what I know:

1. Pin oak
2. large (>30")
3. I don't know ( it was diagnosed by the extension office with a branch brought in by the homeowner)
4. No.


Talk to you soon, Chris
 

bushman

Member
I have pin oak 35db it gets bad bls in the dry summers it seems .i pruned and water deeply and mycor was applied as well to help with water take up.i wonder if bacastat is a every year or every two?I saw it on reds as well this summer.thinking a bigger bed around the tree this year.
 
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