DESCRIPTION: An eriophyid mite is the causal agent here with the affected buds made up of a cluster of swollen leaves. The gall starts silvery green before becoming brown and woody. Inside the gall are a good number of mites which spend most of the year there. After passing winter in a dormant stage they will emerge in the spring and early summer to start the process again on the new buds. DISTRIBUTION: A widespread species but again under-recorded perhaps due to the gall being easily overlooked. HABITAT: Found on the buds of various Birches.