Management of tomato damping off by using plant growth promoting microorganisms

Pythium aphanidermatum is one of the most important pathogens to cause damping off disease in nurseries and a major constraint in the production of tomato. Considering integrated control system for damping off, fungicides were tested alone and in combination with Pseudomonas fluorescens and Bacillus subtilis. The fungicides were also tested in vitro for their efficacy against Pythium aphanidermatum and for compatibility with P. fluorescens and Bacillus subtilis. Bioagent, P. fluorescens and Bacillus subtilis were effective against Pythium aphanidermatum. Maximum per cent growth inhibition was recorded by P. fluorescens (35.37%). It was also observed that growth of P. fluorescens and B. subtilis did not affect due to fungicides except propiconazole @ 0.1%. Amongst fungicides Thiram, Metalaxyl, Fosetyl-AL, Propeconazole were cent percent effective against pathogen at all tests concentrations (0.1%, 0.2% and 0.3%). The lowest per cent growth inhibition was observed in Carbendazim at 24 hr (18.86%) and 36 hr (20.25%). The disease was reduced by the seed treatment of P. fluorescens @ 10g/kg + Metalaxyl @ 2g/kg seed. Combination of antagonists P. fluorescens and B. subtilis were found effective to increase seed emergence (73.78%), shoot length (4.5cm), root length (7.02cm) and vigour index (894.21).