Efficacy of fungicides and phytoextracts against Alternaria spp. causing leaf spot on cotton in vitro.

Of the eight fungicides tested in vitro, mancozeb and hexaconazole were found most effective to inhibit the mycelial growth of Alternaria spp. at 0.2% concentration. Phytoextract, azadiractien was superior over karanz oil and mustard oil to inhibit the mycelial growth. In potted plants, minimum disease severity were obtained in mancozeb and hexaconazole followed by copper oxychloride and tilt. All treatments as foliar sprays were able to reduce disease severity over untreated control at 0.2% followed by 0.1% concentration. Mancozeb and hexaconazole were found effective in management of Alternaria leaf spot of cotton.