Odd Home Found In A Tree

We found these on one of our swamp oak trees while out for a walk and recognized them as galls of some sort.

click on the image for a closer look

 

I sent a photo to a pal of mine who is a forester and he confirmed that these are probably oak apple galls.  They’re caused by a tiny wasp and can form on stems or leaves.  Some years are big years and other times not.  It seems to depend on the weather. 

These deformations occur after a female oak apple gall wasp lays eggs in the central vein on an oak leaf.  When the larvae hatch - a chemical and hormone interaction between the wasp eggs and the oak causes the tree to grow the round gall.  Each gall contains only one wasp and serves as both home and food for the young insect. 

It is a cosmetic condition and as a general rule causes no permanent damage to the tree.  If you find it bothersome simply snip them-off before they dry out.  For us we left them be.  Tiny wasps deserve a start in life and have a role in the forest’s circle of life.