Biosafety Evaluation Of Various Bt Proteins Expressed In Various Transgenic Crops Using Artificial Diets And Improvement Of Artificial Diet Based Mass Rearing Of Three Predators

Fast adoption of genetically modified (GM) crops by the many countries to control destructive insect pests of economic crops has raised question about the safety of GM crops to biodiversity in our ecosystem, because biodiversity is equally important for sustainable agriculture and environment. Biodiversity play important role to keep our ecosystem stable. Somehow it is necessary to evaluate the impact of GM crops on biodiversity to avoid undesirable effects on our ecosystem. Artificial diet is valuable tool to perform biosafety evaluation studies. Therefore artificial diets for key predators were developed to establish dietary exposure tests for biosafety evaluation of Bacillus thuringiensis produced toxins expressed by GM crops.In addition increasing trend in the use of biological control agents in insect pest management in sustainable agriculture and greenhouse pest management have increased the demand for biological control agents i.e. predators and parasitoids. Artificial diet for predators is key factor for increasing fast and cost effective mass rearing to meet rising demands of biological control application.To evaluate safety of GM crops and to promote use of biological control agents for sustaining long term benefits of GM technology was focal point in this study. Artificial diets for Chrysopa pallens, Propylea japonica and Harmonia axyridis were developed and used to establish dietary exposure tests for biosafety evaluation of GM crops expressing Bt proteins and artificial diets were also used to design cost effective mass rearing techniques for commercial production of key predators to promote biological control applications. Following are main achievements of this research.1. Artificial diets were developed and tested for survival and development of immature C. pallens. An artificial diet sustained more than 80% survival of C. pallens. Subsequently this artificial diet was used to develop dietary exposure test for evaluation of environmental risk of Bt proteins (Cry1Ab, Cry1Ac, Cry1Ca, Cry1Fa, Cry1Ah, Cry2Aa, Cry2Ab and vegetative insecticidal protein Vip3 Aa). Outcomes of dietary exposure tests indicated that Bt proteins are safe on C. pallens larvae at high concentration 200μg/g of artificial diet. In contrast, boric acid incorporated artificial diet caused reduced survival and affected other life-table parameters of C. pallens2. For predacious adults of C. pallens adequate artificial diet was also developed and subsequently used to design dietary exposure test for adult C. pallens to evaluate four Bt proteins (CrylFa, CrylAc, Cry2Ab and Vip3Aa). Life-table parameters of adult were not affected when fed artificial diets containing Bt proteins at high concentration, In contrast life-table parameters were significantly affected when artificial diet containing boric acid was fed to adults. The study proves that Bt proteins are safe to C. pallens and cultivation of GM crops expressing Bt proteins pose no detrimental effects on important predators like lacewing C. pallens.3. Three various formulations of artificial diets were prepared and their fitness suitability on immature development, survival, pupation, emergence and freshly emerged adult size on Harmonia axyridis and Japanese beetle Propylea japonica (Thunberg) (Coleoptera:Coccinellidae) were investigated. Results indicated that artificial diet consisting of shrimp, beef, beef liver, egg yolk in proportion 5:4:8:4 is quality source of nutrition for successful immature development with more than 80% and 65% adult emergence in P. japonica and H. axyridis respectively. Impact of artificial diet and pea aphid on survival and reproductive physiology of emerged P. japonica and H. axyridis from immature fed artificial diet or pea aphids were studied and it was found that reduced adult size in artificial diet based rearing do not cause reduction in fecundity of emerged adults. Artificial diet sustained survival of adult ladybirds but no oviposition was observed. However, oviposition was later restored when aphids were fed to both predatory beetles. It indicates that artificial diet can be used to feed adults during prey shortage or during shipment of predators.4. Further suitable artificial diet was used to establish dietary exposure test to evaluate the impact of Bt proteins on immature P. japonica and H. axyridis and dietary exposure bioassay results indicates Vip3Aa is safe for P. japonica. Vip3Aa, Cry IF, CrylCa are safe for H. axyridis. It is concluded that GM crops expressing Bt proteins in single or stacked form are safe to predators.