Evaluation of fungicides against bean rust (Uromyces appendiculatus)

French bean rust caused by Uromyces appendiculatus is an important disease of French bean particularly of pencil types in mid hills of himachal Pradesh. bean rust severity ranges from 15 to 80 per cent and it often appears in epidemic proportions in major bean growing areas resulting in extensive damage and huge losses to the farmers. Present investigations were undertaken with an objective to study the efficacy of different fungicides against bean rust under in vitro and in vivo conditions. Efficacy results retrieved from the experiment revealed that under in vitro conditions minimum urediniospore germination was recorded in zineb + hexaconazole (0.69%) in comparison to (45.26%) germination in control. Minimum germ tube length (15.48 μm) was observed in zineb + hexaconazole as compared to the germ tube length of 149.4 μm observed in control. Under in vivo conditions, though all the fungicides could significantly reduce rust severity in comparison to untreated control (49.33%), yet sprays of azoxystrobin (@ 0.1%) was significantly most effective in reducing the disease severity to 4.64 per cent and also resulted in maximum green pod yield (6.80 kg/plot) whereas yield in control plot was 3.45 kg/plot. Azoxystrobin in addition to the fungicidal activity also exhibited some phytotonic effect which delayed the crop senescence and attributed to enhanced yield of the crop.