Cumin (Cuminum cyminum L.) is one of the oldest field crops grown in upper Egypt. It has an aromatic adore, a spicy, somewhat bitter, taste and is widely used as condiment. It is also used in the industry of medicine, cheese, perfumes and carry. Most of seed production of Assiut Govemorate is for exportation. In recent years cumin crop is subjected to attack with blight disease. Such disease is destructive and caused a great reduction in seed yield and quality. Alternaria alternata and Alt. burnsii and Chaetomium sulphreum are reported to be the casual pathogens of the disease.