Entomopathogenic Fungi as Biopesticides for Sustainable Agriculture

Agriculture productivity today faces many challenges in meeting the requirements of a growing population. Climate change and pest damage are two of the primary constraints for an increase in agricultural productivity. Damage to agricultural crops primarily occurs due to insect pests. Chemical insecticides are used for the control of insect pests on crops and for stored grain insect pests. These chemical insecticides are harmful for humans and other nontarget organisms and also result in ecosystem damage. After a few exposures, the target insect pests evolve to overcome the toxic effects of these insecticides, making them redundant. In order to overcome these drawbacks, a few alternate and environmentally friendly methods have been tested. These include the sterile insect male technique, the use of microbes and their metabolites, the bioprospecting of secondary metabolites from plants, and gene editing technology. Although each method has its pros and cons, the use of microorganisms and their metabolites has emerged as a low-cost, environmentally sustainable method for the control of insect pests. Among the microbes used in insect control, insect pathogenic fungi hold potential to be used as an inexpensive alternative to chemical insecticides. Only a few of these have been commercialized. The popularity of these entomopathogenic fungi is low, as fungal pesticides have a relatively short shelf life; their virulence gets low after long storage, and spore germination is affected by the high temperature and low humidity. Recent studies have shown that modifying the media composition can increase the virulence and shelf life of fungi. Given the diversity of entomopathogenic fungi and their secondary metabolites, there is a huge potential for developing highly effective biopesticides for insect control.