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Subject: Plant Pathology × Author: Bora, Budha × End date: 2019 × Start date: 2015 × Type: Thesis ×
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    ThesisItemOpen Access
    BIOINTENSIVE MANAGEMENT OF SHEATH ROT DISEASE OF RICE CAUSED BY Sarocladium oryzae (SAWADA) GAMS AND HAWKSW
    (AAU, Jorhat, 2019-07) Bora, Budha; Ali, Sakendar
    Sheath rot of rice caused by Sarocladium oryzae (Sawada) Gams and Hawksw has emerged as one of the major diseases of rice. The fungus attacks the boot leaf sheath affecting emergence of panicle resulting discoloured and chaffy grains and inflicts considerable yield loss. The pathogen is seed borne and survives in soil on the leftover stubbles, which acts as the sources of primary inoculums. Many effective pesticides have been recommended against this disease, but not considered as a long term solution because of concerns about pesticide residue risk, health and environmental pollution and health hazards, development of resistance, residue persistence and elimination of natural enemies which necessitates an alternative eco-friendly method for its management and sustainable crop production. The present study was undertaken to evaluate the integrated effect of microbial antagonist, organic amendments and biofertilizer consortia on the suppression of sheath rot pathogen that survives in rice seeds, stubbles and consequential improvement of soil health. Among the different microbial antagonists evaluated, Pseudomonas fluorescens was found to be the most effective inhibiting maximum (82.06%) radial growth of S. oryzae in vitro followed by Bacillus subtilis (7.35%) and B.megatorium (67.38%), respectively. Among the fungal antagonists, Trichoderma harzianum was found to be the most efficient inhibiting maximum (65.21%) radial growth of S. oryzae followed by T. viride (57.76%) and T. asperellum (52.09%), respectively. Talcum powder based formulation of the best microbial antagonist (P. fluorescens) was found to be most effective when applied as seed treatment, seedling root dip treatment and foliar spray at boot leaf stage in reducing maximum disease incidence (68.24%) and percent disease index (57.26%) over control and increased the yield attributing characters such as number of effective tillers per hill, number of healthy grains per panicle, 1000 grain weight and grain yield etc tested under pot condition. Dhaincha (Sesbania aculeata) as organic amendment along with biofertilizer consortia enriched FYM and microbial antagonist (P. fluorescens) was proved to be the most effective method for management of sheath rot disease as evidenced by maximum reduction of disease incidence (69.94%) and percent disease index (60.95%) over control and also found to increased the yield attributing characters under field condition. The S. oryzae could survive only upto 120 days in S. aculeata amended plot followed by 150 days in plots amended with azolla and vermicompost, respectively whereas, it could survive upto180 days in the control plot at different soil depths (0cm, 2 cm and 4 cm) that were evaluated. However, in all the situations, the survival and viability of S. oryzae declined with increase in time. Soil amendment with organic materials along with biofertilizer consortia and microbial antagonist (P. fluorescens) has significantly increased the N, P, K content, organic carbon and microbial biomass carbon. Among all the organic amendments, S.aculeata as in situ green manure crop along with biofertilizer consortia and microbial antagonist(Pf) was found to increase maximum N, P, K (305.4, 17.77, 106.43 kg/ha) content of soil and ranked next to RDF. Moreover, organic amendments have significantly increased the Boron content of soil. Among all the organic amendments, the plot amended with S.aculeata along with biofertilizer consortia and microbial antagonist (Pf) recorded the highest (0.66 mg/kg) B followed by azolla (0.64 mg/kg) and vermicompost (0.63 mg/kg) plot, respectively. Among all the different amendments, S.aculeata as in situ green manure crop along with biofertilizer consortia and microbial antagonist (Pf) recorded the maximum OC and MBC (0.67%, 281.58μg/kg) followed by azolla (0.63%, 273.46 μg/kg) and vermicompost (0.61%, 267.88 μg/kg) plot, respectively. The enhancement of OC and MBC in the dhaincha amended plot over control was recorded to the tune of (23.88%) and (12.86%), respectively and considered as the most effective treatment combination not only in terms of improvement of plant health, soil health and disease suppression ability but also found to enhance the grain yield.