Efficacy of Bio-control agents in Management of Reniform Nematode - Root Rot Complex in Cotton

Comparative efficacy of four bio-agents viz., Trichoderma viride, Paecilomyces lilacinus, Pochonia chlamydosporia and Pseudomonas fluorescens were tested against reniform nematode, Rotylenchulus reniformis - Macrophomina phaseolina root rot complex on cotton cv. CU-5 during 2006–2007. The bio-agents were effective both as seed treatment and soil application. P. fluorescens as seed treatment @ 20 g/ha followed by soil application @ 2.5 kg/ha² was found significantly superior over other treatments recording 62.5% reduction of female nematodes in the root system, 56.4 and 45.6% increase in plant height and root weight, 56.6% reduction in soil population of nematodes and 98.5% increased yield. Seed treatment with T. viride was most effective in reducing the root rot incidence to the tune of 91.9% and was on par with P. fluorescece in respect of yield.