ISOLATION, IDENTIFICATION, AND EVALUATION OF SOME FUNGICIDES FOR CONTROLLING PURPLE BLOTCH OF ONION AND GARLIC IN MINIA GOVERNORATE, EGYPT

Onion and garlic are the oldest vegetables plant species of the Genus Allium. Purple blotch and Stemphylium blight of onion and garlic are important foliar diseases which are induced by the fungi Alternaria porri and Stemphylium versicarium. The survey was conducted in major onion and garlic cultivation villages of three districts in Minia Governorate during winter of 2020 – 2021 season. The survey revealed prevalence of purple blotch and Stemphylium blight in all locations under study. Direct microscopic examination of infected samples proved that either Alternaria porii, Stemphylium sp. or both together associated with the purple blotch disease lesions. Thirty-one isolates of Stemphylium sp. and Alternaria porri were obtained and the identification of the most aggressive isolates of Alternaria and Stemphylium; OAp1and OSv5, respectively, were performed using PCR technique. The pathogenicity test indicated that all tested isolates of both pathogens (S. vesicarium and A. porri) infected onion and garlic leaves causing different degrees of purple blotch and blight symptoms. The evaluation of nine fungicides against the growth of isolates OAP1 and OSV5 of Alternaria porii, Stemphylium vesicarium, respectively, under laboratory experiment revealed that the growth of S. vesicarium was completely inhibited at 200 ppm Ridomil Gold Plus, while Dithane M-45 and Pronto completely inhibited the growth of A. porri and S. vesicarium at 400 ppm.