Cereal production is limited by many different factors. Leaf diseases are often well known, while diseases on roots are more difficult to identify. Root diseases are often caused by oomycetes, fungus-like microorganisms that live for years in soil and on old root debris, parasitizing the roots of wheat, barley, and many other plant species. Adult plants may be stunted and/or chlorotic, as if nitrogen deficient. Symptoms are often difficult to recognize and diagnose. Severe infections cause a general root rot. Within the project group we have noticed both Aphanomyces and Pythium spp. on roots of barley and Pythium spp. on wheat. These pathogens are overlooked and they cause diseases that can be important in all cereal-producing areas. In this project, we aim to identify the pathogens, assess the pathogenicity on different hosts and cultivars in the crop rotation and also evaluate the effects of seed treatments and lime.