22nd January 2025

There's always something intertesting to see, even in January. These are oak apple galls caused by the tiny Oak Apple Gall Wasp (Biorhiza pallida). Eggs are laid in buds on oak trees and this causes the bud to grow deformed. The larvae of the wasp eat the plant tissues inside the gall. On old ones like these, you can usually see the exit holes made by the newly emerged adult wasp.

Oak apple galls