The oats were observed to be the species mostly damaged by Oulema ssp. phytophages which is represented by the highest damage indexes of the plant in all the objects researched. The two other species: barley and spring triticale are much less sensitive to feeding of the pest. The initial damage which was due to the complementary feeding was hidden due to the compensation capabilities of the cereals. Spring barley, which tillers most, compensated for the damage most considerably. The economic harmfulness of the Oulema feeding may be estimated only in shooting phase, when also the larvae start skeleting of leaf blades. In barley and spring triticale a considerably lower larvae feeding was observed when compared with leaf beetles. The co-ordinate cultivation of the researched species with fodder pea and in two-ingredient cereal mixtures enhances the damage reduction caused by Oulema feeding.