Preferência alimentar de Helicoverpa Armigera a diferentes cultivares de soja com tecnologia Bt em laboratório

Abstract

The use of Bt transgenic plants for H. armigera control has been a tool adopted within the pest management plan, however, it is necessary to verify the presence of resistant insect populations. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has been reported to cause damage to several crops due to their high polyphagia and difficult control. In western Bahia was reported the first occurrence of the insect in Brazil in the 2012/2013 crop causing losses of up to 80% in soybean and cotton crops. Thus, the objective was to evaluate the consumption and feeding preference of H. armigera caterpillars in five soybean cultivars containing Bt gene for five days. For the evaluation of attractiveness, H. armigera caterpillars were released in a petri dish containing four leaf discs, two discs of cultivar Bt and two discs of non-Bt cultivar. The data were submitted to the Chi Square (X²) test at 0.05 of significance, and the leaf area consumed was measured with the aid of the ImageJ® program. The tests were performed by R software version 3.5.0. In both attractiveness tests H. armigera caterpillars were observed in all soybean cultivars tested. In the attractiveness test, it was found that the cultivars Desafio and LG 60162 were considered attractive to H. armigera, while the M 7739 IPRO was considered unattractive to feeding H. armigera caterpillars. No Bt toxin mortality was observed.