Atividade inseticida do óleo essencial de Hyptis marrubioides no controle de Zabrotes subfasciatus (Coleoptera, Chrysomelidae, Bruchinae)

Abstract

It´s known that a large percentage of the bean production and storage is lost by insects. This study aimed to evaluate the insecticidal activity of essential oil of Hyptis marrubioides control Zabrotes subfasciatus. The essential oil extraction was performed by the method of hydrodistillation in a Clevenger apparatus for an hour and a half and biological assay was conducted in the Microscopy Laboratory / IFSULDEMINAS - Campus Muzambinho. The experimental design was completely randomized, with five doses of essential oil (0.0, 6.25%, 12.5%, 25% and 50%), with 04 replicates a couple of Z. subfasciatus by repetition. We carried out the test and the test of mortality or inhibition of oviposition repellency. 03 grains used was treated with 05 microliters (μL) of the solution and three untreated, and that in each petri dish of diameter 9.0 cm bed 01 had Z. subfasciatus. As a control, we used 100 μL of 70% alcohol. Under each treatment applied, we observed the reaction of individuals depending on the application of the solution in the grains, indicating that the lethal times (LT) decrease as there is an increase of the applied dose and direct contact with the oil of H. marrubioides. The treatments with essential oil proved to be effective, because they caused repellency, total adult mortality and no oviposition. For the four tested doses, the time interval of 28 minutes was sufficient to induce mortality in all individuals. Besides not observe a significant difference in the average number of eggs of individuals of Z. subfasciatus not subject to the application of essential oil of H. marrubioides (free choice: grain alcohol-treated and untreated). Therefore in this study, we observed the insecticidal potential of essential oil of H. marrubioides, which due to its effective insecticidal properties observed in this study may be useful in integrated management of Z. subfasciatus in stored bean.