Helicoverpa armigera food preference to different soybean cultivars with Bt technology

Abstract

The use of transgenic plants with Bt technology to control Helicoverpa armigera (Hübner, 1805) (Lepidoptera: Noctuidae) has been a method adopted within the pest management plan, however, it is necessary to verify the presence of resistant populations of the insect. Thus, the objective of the study was to evaluate the attractiveness, consumption and food preference of H. armigera caterpillars in Bt soybean cultivars. For attractiveness and consumption evaluation, H. armigera caterpillars were released in Petri dishes containing four leaf discs, two discs of Bt cultivar and two discs of non-Bt cultivar. In the evaluation of food preference, a caterpillar was placed in the central area of the Petri dish and two discs of each cultivar were placed equidistantly, resulting in twelve leaf discs per plate. In both tests, caterpillars were observed in all soybean cultivars. In the attractiveness test it was verified that the cultivars Desafio IPRO and LG 60162 were considered attractive for H. armigera, while the M 7739 IPRO was considered unattractive for H. armigera caterpillars feeding. In the evaluation of leaf consumption, the cultivars Desafio IPRO and LG 60162 IPRO were considered attractive for consumption. Regarding the food preference test, it was found that the cultivar M 7739 IPRO was the one that had the least preference for feeding H. armigera caterpillars. Future works should be developed in order to verify under field conditions whether there is a feeding preference of H. armigera by different Bt soybean cultivars, since environmental factors could interfere with the insect's behavior.