EN
Paper presents the main problems of eriophyoid mites as the vectors of virus diseases of cereals and other grasses. The most important viruses and their vectors are: wheat streak mosaic virus (WSMV) transmitted by Aceria tosichella Keifer, ryegrass mosaic virus (RMV) and agropyron mosaic virus (AMV), transmitted by Abacarus hystrix (Nalepa). Both species are very numerous and frequent in Poland. A. hystrix has been found on 40, and A. tosichella on 15 species of grasses, including economically important species, for instance Triticum aestivum L. The necessity of further studies related to both species are suggested.