[4] Common names include - DE: Haselnussgallmilbe, Haselnuss-Knospengallmilbe, ES: Badoc del avellano, FR: Phytopte du noisetier, IT: Eriofide del nocciolo, GB: Filbert bud mite, Hazelnut gall mite, TR: Fındık kozalak akarı.

), develop as a chemically induced distortion of the expanding leaf buds or female flowers on hazel shrubs, caused by the mite Phytoptus avellanae, several hundred of which can live in a single gall within the 20–40 scale leaves.

At this stage they feed upon the sap and this causes the scales to swell and open up, the stamens distort and eventually disappear.

[2][3] A predatory midge, Arthrocnodax coyligallarum, and a chalcid parasite, Tetrastichus eriophyes are recorded on P. avellanae.

[7] This pest causes important reductions in the harvest, especially as the buds destined to give female flowers and fruit seem to be preferentially invaded.