An Odd Oak Issue

Home Grown  by Keith Reed
We had a very unusual sample from an oak tree brought into the Extension office this week. On first glance, the problem could have easily been misdiagnosed as broadleaf herbicide damage as the leaves were curled and misshapen. However, close inspection revealed an additional issue. On the back side of the leaves, the veins were disfigured and several times their normal size. It almost looked like large green worms crawling along the leaves.

The problem was caused by the vein pocket gall. Galls were a big problem last year on oak trees but it was a different species and the damage was quite different. It is too early to tell if this is going to be a common problem this year but don’t be surprised if you see it. There is no treatment for this issue, and attempts to do so will only waste your money and potentially harm beneficial insects. Even though the tree may not look good this year and could potentially drop its leaves early, this issue should not cause permanent harm.

Other than speaking to those who have trees that are directly affected, I mentioned this issue for another reason….and that goes back to the near miss-diagnosis. When trying to solve a landscape problem, always try to look at it from a “systems” perspective, not just an isolated issue. Factors that may not appear to be at all related could be causing (or at least contributing) to the issue.

Consider factors such as surface water drainage, air movement, recent construction activity, changes in irrigation water source, pet activity, sub-surface issues, unusual weather fluctuations, pesticide and fertilizer applications, etc. A common example from the last few years has been random dry spots appearing in turf areas, even in cases where irrigation is a part of the regular maintenance regime. These have often proven to be either sandstone layers a few inches above the surface or leftovers from old construction such as foundations or broken sidewalks.

In “normal” rainfall years, the turf is able to survive on limited roots because of adequate supplemental rainfall. Without that supplement, the effects of shallow roots become more apparent. Sometimes this is easy to see, but sometimes it requires some effort (including digging) to uncover the cause of the problem.

Whatever the case, try to examine things as carefully and completely as you can before seeking advice. If you are unable to solve the problem on your own, you are at least better prepared to help the experts find the solution.

For more information of this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at
keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

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