JB1
New Member
got these pin oaks, that has what I think is a gall, can you tell me anything about it, whether it can be treated, or is it to far along and needs cut down.
Think its a gall
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Yep, its a gall. Caused by a wasp. Don't recall the specific name. No control measures except prune out existing galls. If heavily affected, consider removal due to overall ugliness.
JB1
New Member
These are big trees, two foot across,they have that all over just like the picture, can they be treated or to far gone , like you suggested.
Urban Forester
ArboristSite Guru
It looks like Gouty Oak Gall. made by a cynipid wasp. There has been some attempts to control the larvae using a soil drench imidicloprid in the early spring, personally I rather doubt it has a very high success rate. These galls are all old, meaning the larvae have emerged (you can see the exit holes in some). In a mature tree like this control is pretty much impossible. Populations of these wasps tend to rise and fall. The key to remember is these galls ARE living tissue, so damage to the tree itself is not threshold. While unsightly its not devastating to the tree.
A) agree control is not going to work.
B) while the population of the wasps will rise and fall, the galls don't come and go (especially the "go" part) with those population changes.
C) I have seen several trees where the galls are severe enough to gridle the twigs. When the ends of enough of the twigs are girdled the tree can start to suffer. I have seen this more on bitternut hickory...but I have seen in on oak (red oak group) as well - shingle oak more frequently than other oaks.
