Potential of biopesticides in sustainable agriculture

Abstract

Sustainable agriculture also aims at increasing the yield of food and fiber crops and reducing the incidence of pests and diseases to such a degree that they do not cause extensive damage to crops. With the advent of chemical pesticides in 1940s, this crisis was resolved to a great extent. But the overdependence on chemical pesticides and eventual uninhibited use of them has caused serious health and environmental problems. This concern has encouraged researchers to look for better alternatives to synthetic pesticides. Biopesticides can make important contribution to sustainable agriculture and help reduce reliance on chemical pesticides. Microbial insecticide like Bacillus thuringiensis (Bt) produces a proteinic toxin which induces paralysis of the midgut and brings about cessation in feeding after being ingested by insect pests. Other promising candidates are Beauveria bassiana and Metarrhizium anisopliae. The spores penetrate the host cuticle, once inside the body, producing toxic metabolites called beauvericin (B. bassiana) and destruxins (M. anisopliae) responsible for death of the insects. Baculoviruses (Nuclear Polyhedrosis Virus and Granulosis Virus) are safe to human beings and wildlife, their specificity is very narrow. They do not infect beneficial insects and have capacity to persist in the environment, making them very suitable for use in sustainable agriculture. Semi- ochemicals: attractants and pheromones, and botanicals are important sources of agrochemicals used for the management of insect pests. They degrade rapidly and therefore, are considered safer than chemical pesticides to the environment. The market for biopesticides is expanding rapidly: growing at some 10% per year, by the end of 2010 global sales are expected to hit the $1 billion mark and make up 4.2% of the overall pesticides market. Further research and development of biopesticides must be given high priority and public in general and agriculturists in particular will force governments to make policy decisions in reducing the use of chemical pesticides. The present paper describes the detailed discussion on the potential of biopesticides in sustainable agriculture.