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diseased oak tree #853199
Asked October 16, 2023, 5:50 AM EDT
Pictured are two oak trees which were simultaneously purchased approximately 20 years ago as 100 gallon trees from the same place and planted in our back yard in Cypress, Texas. While the one on the right seems to be fine, we noticed strange growths in bark on the branches of the smaller tree, in addition to the growth of hard yellow balls. I don't know how long this has been going on since, prior to retirement, I rarely took the time to notice such things. Is this something that can be treated? Is it something that can be spread to our other oak trees if left unchecked? Please advise at your earliest convenience. Thank you.
Harris County Texas
Expert Response
# 0123124 diseased oak tree
Attached More close up images of hard yellow balls growing on oak tree.
Hi, Karen
The photos you sent show oak galls. They can be found on branches, leaves, nuts, and most parts of a tree. They are commonly produced by wasps or mites, but in many situations, wasps. In addition, some can be caused by bacteria or fungi.
They are common on oaks (Quercus species) in Texas and cause little harm. Insect damage causes a reaction from the tree to create deformities that tend to be woody. The holes are where the very tiny wasps emerge.
Control for the gall wasps are not very effective and not recommended.
They are quite fascinating and love that you cut yours in half.
Oak leaf galls | Urban IPM (agrilife.org)
Callirhytis Oak Gall Wasps | NC State Extension Publications (ncsu.edu)
