black fungus on water oak leaf

[DavidT]

I looked at a water oak today that the owner said practially died over night. The tree is full of leaves which have all turned brown. I picked up some leaves off of the ground and on the back of them looked like a black fungus. I removed a water oak for him about 2 months ago that died and he has a 3rd oak that looks like it is dying.

Any ideas?

 

[KTSmith]

Any photos?

 

[DavidT]

Hope this helps

 

[RGus]

Could it be oak wilt? I dont know if it is a problem in your area, but I would imagine a water oak (Quercus nigra) would die pretty quickly from oak wilt, and would explain why multiple oaks are dying on the property.

It wouldnt explain the black fungus on the leaves, but since you picked them up off of the ground it could be a non issue. I would check leaves on the tree for the black fungus.

 

[KTSmith]

The photo is pretty low resolution, but the splotches look to be sooty mold (genus Meliola or Capnodia, at least in the old days). Sooty molds are epiphytes that feed on honeydew produced by piercing and sucking insects such as aphids.
Although sooty molds can reduce photosynthesis and cause premature leaf drop in extreme cases, they don't kill trees.
Lots online about oak wilt. Could start with: http://na.fs.fed.us/spfo/pubs/howtos/ht_oakwilt/toc.htm

Not much else to go on.

 

[SMAdams]

I agree with KT, but it could also be a secondary fungus. A necrotroph, a fungus that grows on dead tissue, could have started growing after the leaf died or was at least compromised enough to lower it's defenses. This would not be the source of the problem, there is probably some other underlying problem.

 

[oldoakman]

We have been seeing a marked increase in Water Oaak mortality here too. Have had moderate drought here this summer. Haven't spoken with anyone ay UGA about this issue. Would like to hear others opinions.

 

[DavidT]

I removed the dead trees yesterday along with another inbetween the 2 that died quickly. Ground the stumps and the soil was real wet. The customer runs his sprinklers everyother day and really soaks his yard. Could he be watering the trees too much?