Efficacy and compatibility of Pseudomonas fluorescens with fungicides in management of pigeonpea wilt

Pseudomonas fluorescens is effective bacterial antagonist for the management of soil-borne diseases. The efficacy and compatibility with fungicides of Pf-2 isolate was tested in vitro and in pots against Fusarium udum, the causal agent of pigeonpea wilt. Pf-2 significantly inhibits the mycelial growth of F. udum up to 42.97% in dual culture. The bioagent was also able to tolerate 0.05 - 0.1% concentration of both Chlorothalonil and Carbendazim in the growth medium in vitro and becomes sensitive with their increased concentrations. In pot culture experiment, minimum number of colonies (10 × 10⁴cfu/g soil) of F. udum and maximum number of colonies (51.11 × 10⁸cfu/g soil) of P. fluorescens were observed in soil treatment with P. fluorescens. Significant minimum incidence of wilt (2.38%) was observed in seed treatment with Carbendazim @ 0.05% + chlorothalonil @ 0.15% which was at par with seed treatment with P. fluorescens + chlorothalonil @ 0.15% as compared to maximum (62.88%) wilt incidence in control. Additionally the plant height, fresh weight and dry weight was also recorded at 120 DAS, in which seed treatment with P. fluorescens @10 g/kg seed significantly increase the plant height, fresh weight and dry weight of pigeonpea. Hence the results concluded that P. fluorescens alone or in combination with chemicals not only reduce the wilt incidence but also enhance the growth of pigeonpea, which ultimately helps in increasing the crop yield.