There are many different bacterial and fungal species used for the treatment of plant diseases. These organisms serve as biological agents in biocontrol. The fungi which are commonly used for the treatment is the Fusarium species. Fusarium harzianum and Fusarium virens are the fungal species which are used against Pythium, Phytophthora, Rhizoctonia, Botrytis, powdery mildew, downy mildew and Sclerotinia.