Effects of the modified Cry1Ab toxin in Spodoptera frugiperda

Abstract

Fall armyworm Spodoptera frugiperda (J.E. Smith, 1797) is the principal corn pest in Brazil, and several countries of the world. An alternative employed for management of thickest is the utilization of the corn transgenic plants that express toxins insecticides produced by the bacterium Bacillus thuringiensis (Bt). However problems caused by the evolution of resistence have challenged of the technology sustainability and limited the crop productivity. In Brazil, among corn Bt technologies currently used for the control of S. frugiperda, technology stands out PowerCore" (PW) wich express the toxins Cry1F, Cry1A.105, and Cry2Ab2. However, the decrease of S. frugiperda's susceptibility to this technology has been reported. An alternative to this problem it is in the use of proteins of Bt modified with greater toxicity for the target pest, and that, above all are able to killing resistant insects. The objectives of this Project are: (1) to evaluate the susceptibility of a population of S. frugiperda resistant to PowerCore technology (Sf-PW) to the different toxins of Cry1Ab; (2) to evaluate the sub lethal effects of these toxins on this population and in offspring. This work aims to provide an important strategy for the insect resistance management, once these genetically modified proteins may have the ability to control insects that are already resistant to current Bt proteins, as well as the Bt technologies that are still being used and there is a risk of field resistance evolution.