Backyard and Beyond

Why, they’re miniature Tribbles! This white oak has been hosting these structures for years now on its leaves. But this is the first time I’ve seen them so fresh. They’ll brown up over the summer.A tiny wasp, Acraspis erinacei, known as the Hedgehog Gall Wasp, creates these in conspiracy with the tree. Essentially the wasp hijacks the tree’s chemistry to protect its young. The tree is not harmed. Come the fall, females will emerge from these and lay their eggs on the oak’s buds. Those bud gall wasps will emerge next year and start the process all over again by moving to the leaf.

All the galls on the blog.