Influence of Microbial Inoculants on Yield and Disease Incidence in Yard long bean (Vigna unguiculata L.)

A farmer participatory research was carried out during the summer season of 2017–18 at farmers’ field of Kollam district, Kerala to study the effect of microbial inoculants viz., arbuscular mycorrhizal fungi and pink pigmented facultative methylotrophs on the pod yield and disease incidence of yard long bean. The experiment was laid out in randomized block design at the farmers’ fields at 7 different locations. This experiment consisted of three treatments; T₁ – farmer's practice (without any microbial inoculants), T_2- Use of Arbuscular mycorrhizhal fungi (AMF) (@ 9 g/pit as basal application, T₃ - Use of Pink pigmented facultative methylotrophs (PPFM) @1% foliar spray thrice at 30 days interval. Significantly higher pod yields were obtained with the use of AMF @ 9g/pit as basal application (14.51 t/ha) compared to PPFM foliar spray @ 1% (12.53 t/ha) and Farmer's practice (10.27 t/ha). Lowest incidence of diseases was also observed with the use of AMF which was significantly superior to both the other treatments. The same treatment also registered the highest net returns and benefit: cost ratio. Based on the results of the study, inoculation with AMF @ 9g/pit as basal could be recommended for Yard long bean for wide spread adoption in Kollam district during summer season.