Efficacy of bio-agents and plant extracts against the alternaria leaf spot of cabbage (Alternaria brassicae)

Abstract

An experiment was conducted to evaluate the effect of three plant extracts, two bio agents and one fungicide in vitro and in vivo against Alternaria brassicae causing leaf spot of cabbage. Among the treatments Trichoderma harzianum @ 2% was found effective in the inhibition of mycelial growth (65.21%) of Alternaria brassicae followed by Psuedomonas fluorescens @ 2% (62.41%), eucalyptus leaf extract @ 10% (58.69%), lantana leaf extract @ 10% (54.96%) and datura leaf extract @ 10% (52.17%). as compared to treated propiconazole (86.95%) and untreated control (00.00%). The plant extracts and bio-agents were tested under field conditions during rabi 2016-2017 for their efficacy against the disease. Among the treatments minimum disease intensity per cent was recorded in eucalyptus leaf extract @ 10% (25.60%) followed by datura leaf extract @ 10% (28.13%), lantana leaf extract @ 10% (25.73%), Trichoderma harzianum @ 2% (29.84%) and Pseudomonas fluorescens @ 2% (30.62%) as compared to propiconazole (treated check) @ 0.05% (25.08%) and untreated control ( 34.05%).