Cambistat for Pin Oak

[RoyD]

I have a 17" diameter Pin Oak in my yard that I am told is infected with bacterial leaf scorch with symptoms of chlorosis. I wonder if anyone has experience with treating this problem with Cambistat? Is this something a tree service should do or is it something within the capability of most home owners? Also, what effect will it have on the lawn grass beneath the tree? Thanks.

 

[kennertree]

Have someone looke at it. Possible causes of chlorosis include poor drainage, damaged roots, compacted roots, high alkalinity, and nutrient deficiencies in the plant. Nutrient deficiencies may occur because there is an insufficient amount in the soil or because the nutrients are unavailable due to a high pH (alkaline soil). Or the nutrients may not be absorbed due to injured roots or poor root growth. One of the most common causes is lack of iron. Have the soil tested and don't worry about the grass. Get mulch over that root zone.

 

[RoyD]

I have had a tree service look at it and he has recommended Cambistat. The tree has lost about 30% of its leaves. The soil is irrigated and a generous application of Ironite has been applied each year. The early leaf dropping began last year. The tree leafed out fully this year but we had a late freeze that got most of the fruit tree buds and probably some of the tree buds as well. This year, however, the leaves began browning up in early summer and had steadily been dropping off the sunny side of the tree. The shady side is still nice and green. I really don't see the leaves yellowing for lack of iron, just green leaves turning brown and dropping.

 

[BayouTree]

If you want to be sure it's BLS you can send off a foliar sample to be tested. Could you take a close-up pic of the leaves? You could see what others here think may be going on. BLS usually has a distinct margin of burn that looks similar to drought stress.

 

[RoyD]

I have had a reply from the University of Missouri and they suggest it might be Tubakia leaf spot. I am sending them some leaves for confirmation.

I have attached one photo here for any comments.

 

[alanarbor]

That does not have the characterstic halo of BLS. I would get lab confirmation before deciding.

Also get your soil tested. If the pH is off, all that iron is being wasted.

Cambistat has a number of benefits beyond just BLS symptom supression.It may help to alleviate some of the chlorosis. It will affect the lawn directly where it is applied.

Of course you don't have lawn right up to the base of the tree, do you? You have a nice big mulch bed around it right?

I would get mulch in there if you don't have it now. Your tree will thank you.

 

[RoyD]

Thanks. No mulch yet but I will get some. I was afraid of smothering the root ball. Since my last posting I have heard back from the Univ. Of MO, where they looked at several photos. They don't think it is BLS either. They think maybe it is Tubakia leaf spot and asked me to send some symptomatic leaf samples to them for analysis. I will do that. Thanks guys.

 

[alanarbor]

Just don't overdo the mulch. 2-3" deep and don't cover the trunk flare. make a large radius of a bed as you can aesthetically handle.

 

[BonsaiJedi]

You can learn more about Cambistat as part of a protocol for BLS here: http://www.rainbowscivance.com/bls/index.asp

Just looking at the one photo it is difficult to say one disease vs another but I agree with the others that it does not look like typical BLS symptoms. The scattered nercrosis rather than a distinct line starting from the tip moving back to the base doesn't look like BLS.
I wouldn't be shocked if it were related more to the chlorosis the leaf is exhibiting rather than a foliar fungus. I've seen this type of leaf spotting on numerous chlorotic pin oaks before. If you were to treat the tree with a proper iron supplement that provided multiple years of green-up all with a program to improve root health you would likely not see a repeat of these symptoms come next fall. Let us know what the path. lab folks tell you about the spots.

 

[RoyD]

Thanks a bunch guys. I feel better about the possibilities for the recovery of the tree now. About five years ago A tree service came out and treated the tree for chlorosis. They drilled a lot of holes around the tree, filled them with Ironite and what they called battery acid. I'm sure it wasn't battery acid but it must have been some acidic liquid. The tree regained its vigor and stayed that way until last year when this leaf dropping began and worsened this year. Does anyone know what the liquid acid was? I have a auger and Ironite but don't know what liquid to pour in the holes.

I will report back on the results of the lab examination. Another photo attached.

 

[huggybear]

Without knowing existing site conditions I'll make a generalized assumption about the idea behind the acidic solution.

Basically different types of trees have a pH sweet spot for the absorption of nutrients (micro mostly). Think about it this way: A pine forest drops its needles which lowers the soil pH (more acidic) which is where the pine trees need the pH to be to absorb the necessary micro-nutrients. A tree that requires a higher pH (more basic) will not be able to grow very well in the pine environment.

So your soil pH may be off for the Pin Oak to absorb the necessary micro nutrient, (ie iron) and by adding the acidic solution essential allows the tree to absorb the micro nutrients more readily.

I honestly never heard of that before though.

Cambistat will help the most because it will allow the tree to absorb more nutrients overall. Mulching also will be beneficial to reduce the amount of watering you will have to do and recycle nutrients.

 

[RoyD]

Hello again. I just received the lab diagnosis from the Univ of MO. They were able to confirm the presence of the Tubakia fungus associated with the lesions on the leaves in a microscopic examination. This is good news in that it isn't BLS.

Thanks for all of the input. I have another question but I will make a new thread for it.

 

[Dixie1]

we are experiencing tubakia leaf spot on several post oaks (Quercus stellata). Some of ours are being defoliated. From what I have read, it is a late season fungal leaf spot. It is recommended that fallen leaves be raked up as the spores can overwinter and reappear next year. not too much to worry about.

http://www.ppdl.purdue.edu/PPDL/weeklypics/8-14-06.html

 

[RoyD]

Thanks. I have been mowing beneath the tree but bagging the clippings including the fallen leaves.

 

[Dixie1]

sounds like you are on top of it.