Alternaria blight

General Information: caused by Alternaria alternata / Alternaria tenuis. Seed borne and soil borne disease. Excessive vegetative growth, close, spacing, and spreading varieties favor disease development.       Symptoms : Water-soaked, small, circular, and purple lesions surrounded by chlorotic tissues on leaflets . Lesions later turn brown to dark brown. The infected flowers die. Circular, slightly sunken, and irregularly scattered lesions on the pods. Affected pods turn dirty black. The pods contain shrivelled seeds.   Lesions on leaflets Died infected flowers

Control :   Sowing late. Adopting wider spacing. Intercropping with linseed. Avoiding excessive irrigation, and vegetative growth. Adopting compact varieties. Seed treatment with thiram 3g kg-1 or vinclozolin or Dithane M-45 (maneb). Foliar application of vinclozolin or carbendazim or carbendazim plus thiram.