Problem in Burr Oaks

RGus

RGus

Location
Minnesota
I have been seeing a problem in the bur oaks in my area. The leaves are wilting on the tree and then the twigs with the wilting leaves are breaking off. Where the twig is breaking off is a very clean break. Where I have seen it, usually either the whole tree or just the top of the tree is affected. Usually it is an individual tree, other trees next to the infected tree are not having the same problem. I have not found any exit or entry holes on the twigs that have broken off from any insects. Anyone have any guesses?

This first pick is of two twigs that had fallen to the ground.
 

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pic of end of the twig, notice how the end of the twig buldges out. Sorry for the blurriness, I just wanted to show how it buldges.
 

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This is what the twig looks like at the breaking point, pretty clean break.

Just a warning that it is a large pic. I wanted to make sure you could see it well.
 

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This last pic is of two mallard hens that were following me around like I was their mother. I almost stepped on them a few times they were getting so close. MMM they sure looked tasty!
 

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I haven't noticed the same problem in the burr oaks around here in Detroit but I did notice in your second picture all the little spots on the leaves. This I have noticed several times on Burr Oaks around me in detroit. These are made by some kind of egg that acts like a mexican jumping bean. I worked next to a tree that over hung a flat roof and the little round eggs had fallen onto the roof and were literally jumping around like popcorn. What are these things and what do they turn into? Do they only occur on Burr Oaks? The leaves seem to remain mostly green, although a little drained and tired looking around the edges.

The jumping beans were about in mid june to early july. I took someone later on to that same Oak but they dissapointed us by not jumping.

In your oaks does this twig bulging phenomenon seem to be killing the tree? How long have you been noticing it?
 
Zac, We are in a bit of a dry spell. The last few weeks were in the 90's. I just saw on the news that WI is in a bad drought, so you maybe a drier than it is here.

Also on the news it just said that farmers in the area are going to get gov. assistance for crops damaged by a late frost this spring. That my have something to do with things.

I have noticed this problem within the last 2-3 weeks.
 
I looked at a tree today with the same problem, and it had branches close to the ground where I didnt need to get up into the tree to look at the infected branches.

It is definatly not a twig pruner, and I dont think it is a girdler either. It is a very clean break, and there is no sign of any insect chewing on the twig.

I think it is weather related, and has to do with bud formation and weak attachments. Not posative about this, but it is what I am leaning towards.
 
Hey guys - I am close to Zac in GReen Lake WI and we have had very little rain this year, and the white and bur oaks are looking awful., this drought was preceeded by last years 24 inches of rain in May and June, then very dry after that. My theory, at least around here is that we had soils that were very saturated last spring/early summer, and we have had little moisture since. I postulate that many of these very old oaks lost a good percentage of thier root mass (anaerobic conditions) last year, nad now they are just plain tired of trying! I likin it to people and pneumonia - if we are inflicted with pneumonia at 40, we usually pull through; if we are 85, well, maybe not.

I am seeing 175 year old white oak tree dying all around the lake here, and many of them lost leaves last year (anthracnose), tried to re-leaf later in summer, but weren't very successful as it was very dry then, and now this spring and summer no moisture. Just my two-cents worth.

Hey Zak, send me an e-mail; I've got a couple of questions to throw by you.

Oh, and thanks for the entomology lesson u young whipper snappers! I must admit, that has never been my forte, but oh how I try!!!

gopher
 
Hi all, I've seen this twig drying/dropping in oaks in Minnesota for the last 5-6 seasons, and that's only 'cause I've been looking. I thought a type of twig girdler at first, maybe an insect that's smaller and is affecting the node like that, but haven't been able to come up with a definitive answer. Seems to happen with white and bur oaks that are also hit by oak anthracnose fungal disease, so perhaps the heavy infection hurries the senescence process???? I'd go for weather related, but then why not in all oaks? It's not squirrels as their chew bites are easily recognized and not clean like that. Hmmm, mmmmmmmmmmmmm. Maybe it's a cellular level physiological response and someone should be pursuing a PhD thesis and get back to the buzz on it.
? R
 
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