Rick wrote:
Anyone seen this before? My neighbors tree has these odd, hard nodules
forming on most of the leaves of his oak tree. A Google search came up bare,
but I'm not sure what to search for anyway. It seems to drop bunches of
leaves all summer, still connected to twigs. Otherwise looks healthy.
http://www.rauth.com/pix/oakleaves.jpg
Thanks,
Rick



Gall seems to be the proper term. There are several different causes but
many are from insects injecting their eggs between the layers of the
leaf which then develop there causing the odd growth. I'd try slicing
some open with a super sharp blade and then inspecting the innards with
a magnifying lens. If you seen little grubs then you have a good idea
what is going on. A Google for "oak leaf gall" (without the quotes of
course) will give you page after page of reading material that may pertain.
--
John McGaw
[Knoxville, TN, USA]
http://johnmcgaw.com