In 1997-1998 the effect of manure. straw and mustard on fungi parasitization of eggs of beet cyst nematode in three years sugar beet rotation was investigated. The highest eggs parasitization by fungi was observed inside cysts from plots with spring barley cultivation and sugar beet as a forecrop. Straw fertilizer favored more fungi parasitization than manure. Three species of nematophagous fungi were isolated from eggs: Cylindrocarpon desiructans. Paeci/omyces lilacinus and verticillium chlamydosporium