DESCRIPTION: Caused by a mite this swollen bud is found in  decent numbers where it occurs locally. The swollen bud is 3-10mm tall and  composed of numerous inner leaves that are fleshy and thick. The galls are  filled with adult mites during the winter months and the following spring the  younger mites move to feed on fresh buds which will duly gall if heavily  infested. Each mature gall can contain all stages of the mite’s life cycle.  DISTRIBUTION: Occasional throughout during May and July. HABITAT: On Yew.