That's unfortunate, but oaks should shake off leaf diseases (literally) & be alright next spring. Really can't guess the origin w/o pics. Black-type oaks suffer a bit more w/leaf diseases than white oaks, typically.

Haven't seen it on oaks here -- they're the ones staying green longer than many other species. Sugar maples lining the slopes & low areas always turn early & rather unspectacularly -- right now in fact. Seems odd -- dryness/heat doesn't make much difference. Planted sugar maples hold leaves later & color better.

That makes me wonder if the wild s maples here are of a northern phenotype that has expanded southward to its limit of summer-heat tolerance & the planted selections are of more southerly lineage.

This post was edited by beng on Sat, Sep 28, 13 at 9:52

Thanks, beng. Red/black oaks as a group do seem far more prone to various pests, diseases, and just general asthetic problems than white oaks do, at least to me.

Which works out well since I generally like the white oaks better anyway (Q. alba and Q. bicolor are my 2 faves). Still, it's a bit disappointing, since some of the affected ones are scarlet oaks that typically have great color around early-mid Nov. after most trees are bare. Won't see that as much this year.

Interesting point about the sugar maples, too. The sugars around here are almost all planted (a few scattered wild ones west and north of here), and a few are showing some early coloration, but appears that they'll have a good strong orange this fall. I think the switch from wet to very dry almost in one fell swoop in mid summer caused a bit of stress, although the sugars look far less stressed than the red maples this fall so far.

It seems like it has been a generally bad year for pests and disease - I think the cool spring and the very wet early summer was a breeding ground for bugs and fungi - the anthracnose was bad this spring esp. on sycamores (but they recovered quite nicely, better than in 2012), and the fall webworms have all but completely defoliated most of the mulberry and walnut trees already. I've seen some oaks iwth some type of caterpillar on them, but not to the point of defoliation.

That's what I was wondering, if the browning on the oaks could be due to feeding from insects or skeletonization to some degree.

I've noticed that here as well. June and July were absolute washouts with us being almost 8+ inches over in rain. August was drier and warmer. I think this somehow tricked many trees into mass defoliation, maybe they thought they were on the savannah and didn't point their feeder roots further down hehe.

The Quercus palustris turns light green first and then it turns brown. This is due to a lack of iron in the soil. You usually only find it on older specimens, probably ones older than 30 years. If you don't treat with iron regularly, the tree will die. It's too bad too because they are an otherwise nice tree. I would avoid planting them because of that.

I have had brown leaves and webs on my White oaks in August. Most are in my lower yard. One Q. Robur English oak has webs and cattipillars on it. A Comptons oak, and several Swamp white oak Q. Bicolor. There was a yellow worm and some green wormies on it. The trees will be dropping leaves anyway, I will buy some BT next year, but for now I'm not worried. I have a Q. Alba that turns a ugly yellow in fall instead of reddish like one about 30 ft across from it.