Changes in cultivation technologies such as growing plants in monoculture, reduced tillage system, no-tillage system and climate changes, caused an increase of importance of some pests of agricultural crops. The following insect species: the bird cherry-oat aphid, the chloropid gout fly, the wheat ground beetle and the European corn borer, occurring previously in a small number and on limited areas, recently have became the major pests of agricultural plants. Cultivation of maize in monoculture is the main factor influencing the expansion of the western corn rootworm (an invasive pest) in Poland.