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K. Manonmani ¹, M. Jayasekhar ¹, M. Muthusamy ¹

Affiliations
1 Krishi Vigyan Kendra, Pechiparai-629161, IN

Abstract

Rice is affected by number of fungal, bacterial and viral diseases. Among the fungal diseases, sheath rot caused by Sarocladium oryzae has been reported to cause considerable loss in yield. Bacterial biocontrol agents viz., Pseudomonas fluorescens (Pf₁) and Bacillus subtilis have been formulated in different carriers viz., gypsum, peat soil and talc powder. Their longevity and biocontrol efficacy against sheath rot incidence were assessed under artificially inoculated condition. The results revealed that gypsum based formulation of two bioagents were effective in controlling the disease by recording the disease incidence of 10.67 per cent and 12.00 per cent respectively. Under field condition also, gypsum based formulation of these biocontrol agents were found to be more effective in controlling sheath rot incidence than the talc and peat based formulations.

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M. P. Uma Maheswari ¹, M. Muthusamy ¹, D. Alice ²

Affiliations
1 Agricultural College and Research Institute, Killikulam, Vallanad 628 252, Tamil Nadu, IN
2 Agricultural College and Research Institute, Coimbatore 641 003, Tamil Nadu, IN

Abstract

The effectiveness of four species of Trichoderma namely T. viride Pres. ex. S. F. Gray, T. longibrachiatum Rifai, T. reesei Simmons, and T. harzianum Rifai, Gliocladium virens J. H. Miller, Giddens and Foster, two bacterial antagonists namely Pseudomonas fluorescens Migula and Bacillus subtilis (Chun) Praznowski and Saccharomyces cerevisiae Hansen was tested against Sclerotium rolfsii Saec. causing jasmine (Jasminum sambac L.) wilt. P. fluorescens, B. subtilis and T. viride were found effective against sclerotial wilt. The volatile metabolites produced by these antagonists were also effective against S. rolfsii in vitro. The sclerotial germination of S. rolfsii was effectively inhibited by P. fluorescens, B. subtilis and T. viride. All the antagonists tested, except S. cerevisiae were effective in inhibiting the production of oxalic acid. Soil application of talc based commercial formulation of P. fluorescens @ 20 g/pot, B. subtilis and T. viride @ 25g/pot effectively reduced the wilt disease incidence in the pot culture experiment.

Keywords

Bacillus subtilis, Jasmine Wilt, Oxalic Acid, Pseudomonas fluorescens, Sclerotium rolfsii, Talc Based Commertial Formulations, Trichoderma viride, Volatile Metabolites.

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