Evaluation of Microbial Consortium for Plant Health Management of Pigeon Pea

Diverse mechanisms are involved in the suppression of plant pathogens, which is often indirectly connected with plant growth. Plant growth promoting microorganisms (PGPM) and biological control agents (BCA) are shown to possess secondary beneficial effects that would increase their usefulness as bio-inoculants, regardless of the need for their primary function. Indeed, PGPM, such as Rhizobium spp., can promote plant growth and productivity (primary effect) but have now been shown to also play a role in reducing disease (secondary effect). Conversely, BCA, such as Trichoderma spp. and Pseudomonas spp., can control disease (primary effect) but have recently demonstrated stimulation of plant growth (secondary effect) in the absence of a pathogen. Based on these beneficial plant–microbe interactions, it is possible to develop microbial inoculants for use in agriculture. Dependent on their mode of action and effects, these products can be used as bio fertilizers, plant strengtheners, phytostimulators, and biopesticides. The use of microorganisms and the exploitation of beneficial plant–microbe interactions offer promising and environmentally friendly strategies for conventional and organic agriculture worldwide. Widely studied and most promising antagonists are Trichoderma harzianum (TH), Pseudomonas flourescens (PF), Rhizobium (Rh) and Bacillus subtilis (BS) have been evaluated in our study for plant health management of pigeonpea in different combinations to make consortia. T 1 (TH+PF), T2 (TH+BS), T3 (TH + Rh), T4 (PF+BS), T5 (PF+ Rh), T6 ( Rh+BS) and T7 (TH+PF+ BS + R). These were inoculated by soil application under green house conditions and in reducing the activity of majority soil borne pathogens. Results in this study indicating that the consortia having PGPR (T5, T4 and T3) performed well in the seedling vigor improvement in pigeonpea. Highest fresh weight of plants at 15 and 30 DAS was recorded in treatments T5 (PF+ Rh), (1.480 g) and T4 (PF+BS) (1.323 g). Whereas Treatments T7 (TH+PF+BS+Rh) (86 %), T2 (TH+BS) (82 %) and T5 (PF+Rh) (77 %) have shown remarkable disease reduction. These results are showing role of biological consortia to play in integrated disease management and plant health management of pigeonpea.