Cola-nut Gall

Andricus lignicolus

Cola-nut galls are created by the asexual generation of gall wasp Andricus lignicolus, which deposits its eggs into the buds of English oak and sessile oak. These galls are scaly and can reach up to 15mm in diameter. They typically occur in clusters of 2-5 and are ovoid in shape. Initially grey when they appear in summer, they mature to a hard brown. The exit hole is usually located close to the point of attachment. Adult wasps emerge in early autumn to lay eggs in Turkey oak buds. The galls are occasionally confused with marble galls; however, marble galls are spherical, larger, and generally smoother in texture.