Wool-Sower Gall (Callirhytis seminator)
I found this on two separate white oak saplings at my parents home.
Text below from NC State University --
The wool sower gall is caused by secretions of grubs of a small gall wasp, Callirhytis seminator. The wool sower gall is specific to white oak and only occurs in the spring. The galls contain seed-like structures. The gall wasps develop inside these structures.
(This gall is also called the oak seed gall.) Fortunately, wool sower galls are usually never abundant so that the health of infested trees is rarely threatened. These wasps probably lay their eggs in midwinter and the eggs hatch just as the new growth emerges in spring. By the time the galls are noticed, it is too late to effectively control the gall wasps. Wool sower gall wasps probably have an alternate generation of wasps which develops in galls in the buds, twigs or on the leaves.
