The present study was carried out to evaluate the incidence of infestation with black vine thrips, Retithrips syriacus Mayet [Thysanoptera; Thripidae] and red European mite, Panonychus ulmi (koch) [Acari: Tetranychidae] on three grapevine varieties in Assiut Gover-norate, during two successive seasons (2005-2007). Generally, the population of R. syriacus was greater than that of P. ulmi in both investigated seasons. The highest population numbers of R. syriacus were recorded during June and July in the first season (2005 / 2006) and during September in the second one (2006 / 2007), on the grapevine varieties (Flame, Thompson and King Rubby). However, the peak of P. ulmi population generally occurred during May and June, in both investigated seasons. Meanwhile, the lowest numbers were recorded during December and January of the first season and during March and April of the second one. With regard to the yield, King Rubby variety exhibited the highest yield, while the lowest yield was that of Thompson variety. In view of the plant content of N, P and K, it was quite obvious that nitrogen and phosphorus positively affected infestation by both pests, while potassium affected negatively