Efeito do óleo essencial de mostarda sobre Sitophilus zeamais (Coleoptera: curculionidae) e em grãos de milho armazenados.

Abstract

Maize weevil, Sitophilus zeamais Mots. (Coleoptera: Curculionidae), is considered one of the most important pests occurring in stored grains. It attacks intact grains reducing grain quality, and consequently, the commercial value of the product. Seeking new alternatives to control these pest insects, this work aimed to evaluate the insecticide action of the essential oil of mustard on different developmental phases of S. zeamais and its effect on stored maize. In order to evaluate the insecticide action of the oil, egg, larvae of first and second instars, pupa and adult phases were exposed to concentration of 50 μl/l of the oil during 24 h. After this period, the grains were maintained in climatic chambers until completing the insects life cycle, and the number of insects emerged in each developmental phase was recorded. For quantitative evaluation of the oil-treated and non-treated grains, tests on apparent specific mass and infested grain percentage were carried out. It was observed that the essential oil presented toxicity in all the developmental phases of S. zeamais and that maize grains stored during 60 days were not quantitatively affected.