Vermicompost- A Suitable Medium for Delivering Consortium of Bio Inoculants into the Rhizosphere of Black Pepper

Abstract

Vermicompost amended with suitable combinations of biocontrol agents and biofertilizer organisms were tested for their effect on plant growth and disease suppression in black pepper in planta. The biocontrol agents viz. P. aeruginosa (MTCC 5178 and MTCC5411), Curtobacterium luteum (strain TC 10) an endophytic bacteria, T. harzianum (MTCC5179), P. chlamydosporia (MTCC5412) and strain of biofertilizer organisms viz. Azospirillum sp. (N 2 fixer), P. fluorescens (P-solubilizers) and Paenibacillus glucanolyticus (Potash mobilizer) were used in the study. These strains have been individually proved as efficient in disease suppression and growth promotion in black pepper. Since these organisms are applied almost at the same time for different functions such as Phytophthora and nematode suppression, growth promotion etc, it is intended to develop a consortium holding all the potential organisms together in a common base media so that all of them can be introduced into the rhizosphere environment in a single application, that not only save time but also economical by way of reducing the cost of application. Vermicompost was selected as the base medium and the organisms having specific functions were individually tested for their growth and proliferation in vermicompost both under sterile and non-sterile conditions. The result showed that both non-sterile and sterile vermicompost supported the growth of all the targeted organisms except Pochonia chlamydosporia that showed a negative trend. When this bio-amended vermicompost medium was applied to the plant base and challenged with Phytopthora capsici, the consortium holding P aeruginosa (strain IISR 853) + T. harzianum + biofertilizer showed comparatively significant growth when compared to all other combinations. However, the lowest disease incidence (5.6%) was observed with P aeruginosa (strain IISR 6) + biofertilizer organisms. Since P aeruginosa (strain IISR 853) + T. harzianum + biofertilizer showed increased growth and at par with the best combination for disease suppression, it is possible to use this consortium also for the better growth and disease suppression in black pepper. Crop losses due to foot rot caused by Phytophthora capsici is recognized as one of the major causes for the low productivity of black pepper in India. The pathogen infects all parts of the vine