RECENT ADVANCES IN THE GENETIC IMPROVEMENT OF NATURAL ENEMIES IN INSECTS, A REVIEWN.N. Singh, A.K. Mall2 and V.K. Mishra
Predators, parasitoids and pathogens have been successfully employed in many cases to control insect pests in an efficient, cost-effective and permanent manner. The global climate change is beginning to affect agricultural systems worldwide and may have impact on the physiology and performance of natural enemies. The indiscriminate usage of pesticides reduced the survival of natural enemy and finally hostile, resource deficit, fragile and ecologically unstable man-made ecosystem has drastically reduced the efficacy of biocontrol agents. The traditional tactics viz., classical, augmentation and conservation have been vital and valuable tools. But emerging technique involving the genetic improvement of natural enemies of arthropods through selection, Microinjection, Paratrasgeneis, Transposable elements, hybridization or recombinant DNA technology offers great promise and also developing superior natural enemies with specific traits like temperature tolerance, insecticide tolerance, increased virulence and amenability to mass production in various natural enemies. The ability to manipulate the genomes of many insects has become a practical reality over the past 15 years. This has been led by the identification of several useful transposon vector systems that have allowed the identification and development of generalized, species-specific, and tissuespecific promoter systems for controlled expression of gene products upon introduction into insect genomes. The genetic fitness and adoptability of biocontrol agents to different agroecosystems is the key for success of biological control programmes. The panacea in concern to regulatory and political issues remain to be resolved before they can be used in practical pest management programs.The egg parasitoid, Trichogramma chilonis tolerant to endosulfan has been developed through artificial selection for 341 generation and this strain has been further developed for multiple resistance to monocrotophos (540ppm) and fenvalerate (20ppm). Using a maternal microinjection technique to transform Braconid wasp (Cardiochiles diaphaniae) with a plasmid containing the paraoxon resistance gene. example overexpression of Bbchit1 gene in transgenic Beauveria bassiana. However, to date only one transgenic arthropod natural enemy, a transgenic strain of the predatory mite, Metaseiulus occidentalis has been released on an experimental basis. Meanwhile, the genetic improved beneficial arthropods through artificial selection and hybridization continues to be explored in pest management.
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