Manejo de Callosobruchus maculatus (Fabr.) (Coleoptera: Chrysomelidae, Bruchinae), em grãos de caupi, Vigna unguiculata (L.) walp. com óleos essenciais

Abstract

Among the pests that attack stored beans Vigna unguiculata (L.) Walp. stands out the cowpea weevil Callosobruchus maculatus (Fabr., 1775), responsible for qualitative and quantitative losses. The use of synthetic fumigants and protectors are widely used on its control, however alternative products such as powders and essential oils of plant origin, have been extensively investigated in recent years, with promising results. Thus, this study aimed to: (a) perform the chromatographic analysis and mass spectrometry in Eucalyptus. citriodora Hook., Eucalyptus. staigeriana F., essential oils; (b) evaluate the toxicity by contact and fumigation; (c) test the repellent effect. The major component of E. staigeriana essential oil was limonene (28.73%) and geranial (15.20%), and for E. citriodora essential oil was Citronelal (89.59%) and Citronelil acetate (3.34). The LC50s of F. vulgare, E. citriodora, E. staigeriana and C. winterianus oils in contact tests were estimated in 4.19, 7.09, 7.44, 7.93μL/20g of bean, respectively. According to regression analysis, the higher the mortality rate, lower was the number of eggs laid and emerged insects. In fumigation tests for adults, the LC50s ranged from 2.58 to 7.85 μL/L of air and the toxicity reasons from 1.25 to 3.04. In all concentrations tested, E. citriodora and C. winterianus oils were repellent to C. maculatus adults. F. vulgare was classified as neutral, while E. staigeriana was neutral at low concentrations and repellent only at the highest concentration 12μL/20g of cowpea. The percentages of reduction of posture caused by the oils esssenciais ranged from 3.26 to 100% and adult emergence from 0.46 to 100%, especially C. winterianus that the highest concentration (15μl/20g), reduced by 100% these parameter.