Organic amendments to soil inoculated arbuscular mycorrhizal fungi and Pseudomonas fluorescens treatments reduce the development of root-rot disease and enhance the yield of Phaseolus vulgaris L.

Root-rot caused by Rhizoctonia solani is a destructive disease of French bean (Phaseolus vulgaris) in the northern plains of India. A randomized block design field experiment was laid out in loam soil containing low organic carbon, nitrogen and medium available phosphorus to evaluate the disease controlling potential of soil inhabiting arbuscular mycorrhizal fungi (AMF) and bacteria. Plants treated with AMF either alone or in combination with Pseudomonas fluorescens, could endure the root-rot incidence under field conditions and produced higher pod yield. Combined inoculation of AMF + P. fluorescens was more effective for controlling the disease as well as increasing the yield. Addition of mustard oil cake to dual inoculation i.e. AMF +  P. fluorescens was found highly effective. AMF + ½ dose chemical phosphorus also improved pod yield and 100-seed weight even in R. solani infected plants. Mixed inoculations along with mustard oil cake were found best treatments for root-rot disease control management.

► AM fungi and PGPR are effective biocontrol agents against soil-borne pathogenic fungi. ► Use of agricultural bye-products makes the technology cost effective and affordable. ► AM fungal action improves in combination with PGPR and mustard oil cake. ► Biofertilizers minimize the usage of chemical fertilizers and related pollution. ► Soil-microbes are useful for sustainable agriculture and human welfare.