Toxidade e repelência de óleos essenciais no manejo de Zabrotes subfasciatus (Boh.) (Coleoptera: Chrysomelidae, Bruchinae) em grãos de Phaseolus vulgaris L.

Abstract

The bean species, Phaseolus vulgaris (L.), stands out as the most important of the five cultivated in the world. Among the pests of stored beans in Brazil, Zabrotes subfasciatus (Boh.) is considered the major one, whose control is commonly carried out using synthetic protectors and fumigants. New approaches to control have been tested, using less toxic compounds, less expensive, accessible and appropriate to the principles of Integrated Pest Management (IPM). The aims of this study were: (i) toxicity test (contact and fumigation) and repellence of dos Eucaliptus staigeriana F. Muell, Eucaliptus citriodora Hook, Ocimum gratissimum (L.) and Foeniculum vulgare Mill essential oils; (ii) identify and quantify the constituting compounds. The analysis by GC/ME indicated the presence of Limonene (28.73%), Geranial (15.20%) and Neral (12.16%), as main constituents of E. staigeriana oil; and for E. citriodora oil, Citronellyl acetate (3.34%), 1,8-Cineole (2.87%) and β-Pineno (0.94%). Among the oils tested at fumigant action, the most effective in controlling Z. subfasciatus were: O. gratissimum (LC50 = 0.9 μL/L air) and E. citriodora (LC50 = 0.9 μL/L air). In contact tests the highlights were: E. staigeriana (LC50 = 2.73 μL/20g) and F. vulgare (LC50 = 2.74 μL/20g). E. citriodora resented repellent effect from the concentration of 7.6 μl/20g of beans seeds, followed by E. staigeriana 8.0 μl/20g. The oviposition reduction of Z. subfasciatus was 96.2%, 96.4% and 57.2%, respectively, for E. staigeriana, E. citriodora and F. vulgare oils. Similar results were found to adult emergence.