Pests constitute a significant threat to the cereal crops on environmentally friendly farms in the south-eastern areas of the country. They cause losses in the seed crops, both directly and indirectly: damaging the plant tissue, pests make the plants vulnerable to bacterial, viral, and fungal infections that additionally lower both the quantity and the quality of seeds. The aim of our research was to determine the species composition of the pests that damage the plants and the level of their harmful effect on selected corn species. The analyses showed that the most harmful corn pests in the area were: the frit fly, the aphids, the leaf beetles, the thrips, the gout fly, the flower midges and the blade midges.