In case of fungicidal trails all the treatments reduced the disease severity in comparison to unsprayed plots. The severity of disease after eight spray of Mancozeb @ % was found minimum disease severity ( %) followed by seven spray ( %) and six spray ( %), respectively. | Effect of mancozeb on disease severity infection rate and seed weight of mustard Brassica juncea L. Czen Coss. Caused by Alternaria spp.