Microbes as biocontrol agents

Abstract

Phytopathogens pose a major threat to ecosystem stability and food production, indicating the need for developing methods to control the severe losses caused by these pathogens. To control these pathogens, the use of various chemical pesticides is majorly practiced. These pesticides are associated with environmental and health hazards and also pose a risk of resistance development in phytopathogens against them forcing the researcher towards the development of alternative and innovative methods by which sustainable management of plant diseases can be achieved. To control plant diseases and have pesticide-free food worldwide, the use of natural antagonistic microorganisms known as biocontrol agents or biological control agents (BCA) is employed. BCA can act on these pathogens through a number of mechanisms such as antibiosis, hyperparasitism, enzyme production, induction of plant resistance mechanisms and competition for essential nutrients and space and through plant growth promotion. Apart from controlling phytopathogens, these microbial agents also promote plant growth and stress tolerance. BCA can be used as bioinsecticides, bionematicides and biopesticides. They are also used for the management of post-harvest diseases. Recently, recombinant microbes have been developed with enhanced biocontrol capabilities. Several commercially available BCA are currently being used for the efficient control of plant disease with improved productivity of many crops. These majorly include GB34, Kodiak, Serenade and Companion containing Bacillus as the active ingredient, Biosave 10LP and Bio-jet containing Pseudomonas as the active ingredient and Soilguard, Trichodex and Trichojet containing Trichoderma as the active ingredient. Thus, use of microbes such as fungi, bacteria, yeast and viruses holds an enormous potential as biocontrol agents to replace conventional chemical-based pesticides and provide food security in a safe and eco-friendly manner.