Bioformulation of Trichoderma harzianum Rifai for Management of Soybean Stem-Rot Caused by Rhizoctonia solani Kuhn

Abstract

In vitro osmoticant (manitol) amended and osmoticant free media of potato dextrose broth (PDB), modified Richard's broth (MRB) and Czapek dox broth (CDB) were tested for biomass production of Trichoderma harzianum Rifai. Osmoticant amended MRB was found best for production of maximum sporulation, cfu and dry weight of biomass of the antagonist, Osmoticant amended media produced higher biomass of T. harzianum than osmoticant free media. Growth and sporulation of T. harzianum was assessed in different carrier viz. starch, talc and molasses enriched charcoal powder (MECP) based formulation. Starch and MECP based formulation of T. harzianum showed increased trend in sporulation of the antagonist upto 60 days, but after this, viability of T. harzianum was abruptly decreased. Talc based formulation-exhibited gradual declining trend in multiplication and sporulation of T. harzianum after 30 days onwards. Among the nine formulation evaluated for growth and sporulation, starch based formulation alone performed best upto 60 days, followed by MECP based formulation. But after 60 days onwards, talc based formulation @ 3: 1 dose showed highest sporulation and maximum cfu, followed by starch formulation @ 1: 1 dose. The overall performance of talc-based formulation was better for growth and sporulation of the antagonist. Potentiality of T. harzianum as seed treatment with talc based T. harzianum and chemical were assessed field condition against Rhizoctonia solani causing stem rot disease of soybean. Lowest disease index and highest % seed germination was observed when seeds were treated with formulation of T. harzianum + talc + osmoticant formulation with enhanced plant vigour and yield of the crop.