Taxomyia taxi

Yew gall midge

Description

This gall midge has a two-year cycle. In May/June the gall midges deposit their eggs on the leaves or buds of yew. The larvae burrow into the bud, where they spend the first winter. Infested buds look no different from healthy ones at this stage. In May of the second year, they start to develop into 1-3 cm long artichoke-like galls. The 3^rd instar larvae overwinter in the buds and pupate in May. A small fraction of the population is univoltine, with the artichoke gall already forming in the first year. They have no impact on the few autochthonous yew stands in Central Europe. Where yew is an ornamental in gardens, parks and tree nurseries, the galled shoots may impact the ornamental value, especially as they turn brown after the midges have left. The preferred habitats are gardens, parks and tree nurseries.