ABSTRACT
The microbial biostimulants are gaining attention as a part of renewable, integrated nutrient management, sustainable agriculture and organic farming in terms of increasing the soil fertility and health, crop productivity and crop quality. This chapter mainly focuses on commercially available bacterial and fungal microbial biostimulants, which serve as biofertilizers and biocontrol agents for agriculture in India. The biofertilizers include nitrogen-fixing bacteria (Rhizobium, Azotobacter, Azospirillum and Acetobacter); phosphate-, zinc-, potassium-, silicate- and iron-solubilizing bacteria; and lignocellulolytic bacteria. The biocontrol agents including Pseudomonas fluorescens, Bacillus and Trichoderma species that serve as bactericide and fungicide are covered. In India, the biostimulants, biofertilizers and biocontrol agents are governed by Fertilizer Control Amendment Order, 2020, Fertilizer Control Order, 1985, and Section 9(3), the Insecticides Act, 1968, respectively. It is important to note that some of the microbial biostimulants function as multifunctional agents through diverse mechanisms. The critical aspects of biofertilizers such as culture characteristics, carrier-based production, applicable crops and commercially available brands are discussed. In the case of biocontrol agents, the spectrum of antagonistic activity, controlled plant diseases, suitable crops, commercially available formulations, delivery mode and multitargeted mode of action is detailed. Further, the popularization of microbial stimulants by the government and private agencies and constraints in commercial production are outlined. The law enforcement agencies should regulate the farmers and limitations such as fake products, quality control and pricing. Further studies are envisaged on colonization potential, variable field efficacy, multistrain formulation design, multilocational and multicrop field trails, etc.
