Eriophyes vitis, common on the Kabareck variety of grapevines was sampled after experimental infestation with 10, 11-30, 30-50 and 50-100 mites/plant, before and after blossoming in Turkey, during 1999 and 2000. The highest number of adults and larvae was recorded in the beginning of August on plants infested with 10-30 mites. When infested after blossoming, 2876 and 3050 mites (1999 and 200, respectively) were estimated. The yield loss is significant (500-700 g.) The necessary struggle againts E. vitis was determined when 11-30 mites are seen by plant before blossoming.