Perspectives of Microbial Metabolites as Pesticides in Agricultural Pest Management

Abstract

In the present-day agriculture, crop protection has become an inevitable event to sustain production. Chemical pesticides are considered to be an excellent strategy to any given pest problem, but overreliance on them raised different environmental concerns besides being ineffective due to resistance development. At this juncture, microbial pesticides had emerged as an alternative strategy due to high target specificity and ecological safety. Although a variety of microbes (bacteria, fungi, and nematodes) are commercially available and in the process of development as well, the actual pathogenicity and host killing are achieved by the metabolites they produce. So, it is obvious that the selection of a strain of any given microbes for pest management is a function of pesticidal metabolites it produces and their bioactivity against target pest. With the advances in applied microbiology and genetic engineering, isolation and characterization of bioactive genes and their products of microbial origin had become one of the fast-growing wing of pesticide chemistry. These efforts lead to commercialization of avermectins and spinosad, the biopesticides with metabolites of microbial origin as active ingredients with wider application in pest management. This chapter includes pesticidal (insecticidal, antifungal, antibacterial, and nematicidal) activities (target pests, modes of action, chemical structures, etc.) of different metabolites produced by diverse pathogenic microorganisms of agricultural importance. The molecular modifications for improving bioactivity, biotechnological approaches, and commercial implications of these microbial origin metabolites are also discussed in view of the existing literature.