The cherry gall wasp, cynips quercusfolii, is a tiny gall wasp that causes growths, or 'galls', on the undersides of oak leaves. The grub remains in the gall after leaf-fall, emerging as an adult wasp in winter. This asexual generation will lay its eggs on the oak tree trunk, which eventually mature to the sexual generation; this generation mates and produces the more obvious galls.
How to identify
The cherry gall wasp produces small, round, red-and-green galls on the undersides of oak leaves.
Did you know?
Female gall wasps lay their eggs on their host plants, which causes the plants to swell up into characteristically odd shapes. The larvae feed on the plant tissue inside the galls.
