ABSTRACT
Biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria and certain minerals. The term ‘Biopesticides’ encompasses a broad array of microbial pesticides, biochemicals derived from microorganisms and other natural sources and processes involving the genetic incorporation of DNA into agricultural commodities that confer protection against pest damage (plantincorporated protectants). Some microbial pesticides such as Bacillus thuringiensis have a long history of safe and effective use as a biological insecticide (Sudakin 2003). More recent developments in microbial pest control include the utilization of other bacterial and fungal species that may competitively inhibit the growth of pathogenic and toxigenic microorganisms on important commodities. The use of microbes and their gene products introduces additional considerations to the toxicological dose-response relationship, including a need to determine the plausibility of infectious and immunological effects in association with human exposure to these biopesticides in food or the environment
BIOPESTICIDES 15 (Sudakin 2003). By developing pest-specific control agents and decreasing the use of broad-spectrum insecticides, one can reduce economic losses caused by pests while minimizing adverse effects on the environment. The advent of biotechnology, and more recently of genomics, has permitted the development of target-specific biopesticides. Of the several thousand genes in insect DNA, many will encode insect-specific biological processes. The challenge is to identify these genes so that a solution for controlling an insect can be designed around them. Tampering with insect genes in an environmentally friendly way is also a challenge. Fortunately, insects are frequently infected by natural pathogens that are harmless to humans or other animals and which could be recruited to deliver ‘geneinterfering’ payloads. The powerful techniques provided by molecular biology and genomics will allow to devise better and more potent control methods that are not only pest specific but also environmentally benign. Biopesticides are primarily natural products or organisms that are compatible with integrated pest management. They have broad modes of action which avoids resistance problems that may exist with some conventional products. Biopesticides often work best in rotation with conventional products so that optimal pest management can be obtained (Griffiths 2007). Generally, biopesticides exhibit the following characteristics: (Nirakar 2007)
• Narrow target range • Highly specific mode of action • Suppress pests, not eliminate • Critical timing of application • Limited field persistence • Smart residual effect • Safer to environment • Safer to people • Biodegradable • Reduce synthetic pesticide use
and residues, hence greater public acceptance
• Production is relatively inexpensive • A renewable resource Biopesticides use is best as part of an Integrated Management Programme (IPM).
