Toxicidade de extratos etanólicos de espécies vegetais para o Callosobruchusmaculatus

Resumo

This work was carried out at the Federal University of the West of Bahia Barra campus, with the objective of studying the toxicity of ethanolic extracts of botanical insecticides, on adult mortality of Callosobruchusmaculatus, by means of time response assays in cowpea. The ethanolic extract was obtained from the crushed seeds of the species Caesalpiniapyramidalis(Catinga de Porco) on the adults of C. maculatus. Lethal times were estimated for 30, 50, 70 and 90% cumulative adult mortality for each concentration. Concentrations of 0, 50, 70, 100, 150, 180 and 200 mg/L were used, which were obtained by weighing and the others by dilution. Insect mortality was evaluated after 24h and extended to 120h after assembly of the bioassays that were conducted in a completely randomized design with four replicates. Mortality occurred in the first 24 hours of exposure, however, the concentration of 180mg/L was the most efficient where mortality was higher than 80%, at the end of 72h exposure the population was completely exterminated and this concentration caused greater Mortality in shorter periods of exposure. The lethal concentration that caused mortality of 50% of the population was LC₅₀ = 17.6 mg/L. In this way, it is possible to recommend the ethanol extract of Caesalpiniapyramidalis at 180 mg/L for alternative use in the control of C. maculatus during storage.