Studies on the behavior of Helicoverpa armigera in relation to soybean cultivars expressing Bt proteins are fundamentally important for IPM. We determine the no-choice and feeding choice of H. armigera, the no-choice and oviposition choice in different Bt and non-Bt soybeans cultivars. In the first step it was carried out the experiment to determine the no-choice and food choice in test for 12 Bt and non-Bt soybean cultivars. Simultaneously the consumption was determined. In a second step it was evaluated the no-choice and oviposition choice in different soybean cultivars. Helicoverpa armigera caterpillars showed neither attractiveness and preference for food nor attractiveness and oviposition preference for Bt and non-Bt soybean leaves when simultaneously contrasting the tested cultivars. This study showed that Bt toxin did not influence the oviposition preference, and H. armigera adults did not differentiate Bt and non-Bt soybean cultivars for oviposition indicating no behavioral preference. Third instar caterpillars showed no discrimination between Bt and non-Bt soybean leaves. Research in this area must focus on the possibility of widespread planting of genetically modified soybeans containing the Bt protein, which is associated with selection pressure and the behavior of pest species in relation to their hosts, as well as on the adequacy of management tactics that is able to prevent the loss of technology efficiency.

Exposure of Helicoverpa armigera to sublethal concentrations of insecticides can cause physiological deficiencies manifested by reduced longevity, development, fertility and fecundity. Research on the sub-lethal effects, to identify the non-lethal negative impacts of insecticides on pests can provide practical information for integrated management. The objective of this study was to determine the lethal concentrations and sublethal effects of insecticides on larval development and reproduction of H. armigera. The insecticides were diluted in water and applied via immersion of soybean leaf discs directly in the solution for three second, subsequently provided to the larvae maintained under controlled conditions for a period of 48 h. For surviving larvae, artificial diet was provided with daily evaluation until pupation. The pupae obtained were weighed after 24 h and transferred to Petri dishes, covered with filter paper until the adult phase, to evaluate longevity and pupal viability. For the assessments related to oviposition, couples were separated in polyvinyl chloride (PVC) cages and fed with 10% honey solution; the counting of eggs was done every two days, until the end of the oviposition period. All of the insecticides tested presented lethal and sublethal effects on the parameters weight, mortality and pupal viability and reduced oviposition and can be used in pest management, representing an alternative in the product rotation for the control of the third instar of H. armigera.