Alternaria blight caused by Alternaria brassicae (Berk) Sacc. and A. brassicicola (Schw) Wiltshire is one of the most common and destructive disease of rapeseed- mustard. The experiments were conducted under field condition to develop effective management strategies for this disease through evaluation of genotypes for resistance and application of fungicide, bio-agents and botanical. Out of 200 promising genotypes evaluated for resistance, none of the entry was found resistant, twenty two genotypes namely DLSC-1, DRMR-261, DRMR-270, GSC-101, GSL-1, NPC-20 and PHR-2, CNH-11-13, CNH-11-7, EC-552608, HNS-1001, PAB 04-10, PAB 05-16, PAB 05-19, PAB 09-05, PAB-2004-4, PAB-2005-16, PPBJ 5, PPBJ-2, PPBJ-3, PPBN 3 and PPBN-2 were moderately resistant and 63 genotypes moderately susceptible. Seed treatment with Apron @ 6g/Kg seed and spray of all fungicides, bio-agents and botanical extract, significantly reduced the blight severity in comparison to the untreated control (water spray). Of the fungicides, Nativo @ 0.05% was found most effective followed by Difenconazole @ 0.05%, Iprodione @ 0.2, Folicure @ 0.2, Difolatan@ 0.2, Mancozeb @ 0.2, Antracol @ 0.25, Pseudomonas fluorescens @ 1.0, Trichoderma harzianum @ 1.0 and Garlic bulb extract @ 1.0 which showed 8.70%, 14.62%, 16.27%, 16.41%, 18.54%, 20.51%, 21.42%, 24.27%, 25.42%, and 26.83%, severity, respectively after third spray of each chemical, bio-agents and botanical extract. The disease severity of water spray control was 69.10%. Same tread was also recorded with per cent disease control. Maximum seed yield (kg/ha) and yield increase (%) of 1740.22, 37.90 was recorded with the treatment Nativo @ 0.05% followed by Difenconazole @ 0.05% (1629.61, 29.16), Iprodione @ 0.2 (1617.11, 28.17), Folicure @ 0.2 (1587.50, 25.85), Trichoderma harzianum @ 1.0 (1525.68, 20.93), Difolatan @ 0.2 (1516.98, 2024), Pseudomonas fluorescens @ 1.0 (1512.37, 1987), Antracol @ 0.25 (1511.45,19.80), Mancozeb @ 0.2 (1507.99, 19.52), respectively. The maximum benefit cost ratio 1:12.60 was obtained with Garlic bulb extract @1.0 followed by Trichoderma harzianum @ 1.0 (1:6.0), Nativo @ 0.05% (1:4.01), Pseudomonas flurescence @ 1.0 (1:3.79).

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