Biology of Dryocosmus kuriphilus

The cynips has a single-parent reproduction (without mating) which produces only females. This reproduction produces a large number of individuals, about 100 to 150 eggs per female. The eggs are deposited in the buds in groups of 3 to 5 eggs between June and August.

The first instar larvae overwinter in the buds, without any external symptoms being visible. In April, at bud break, galls of 5 to 20 mm form as the larvae feed. The larvae pupate between May and July and the adults emerge and fly out between June and August.