Medidas de controle do Sitophilus zeamais em sementes de milho armazenadas com extratos de Piper nigrum L. e Annona squamosa L.

Abstract

The Sitophilus zeamais is the most important pest of the stored maize (Zea mays L.) in tropical and subtropical regions. In order to minimize the undesirable effects of synthetic chemical insecticides, the control of this pest with plant extracts has formed a low cost and safe promising alternative for applicators and consumers. The aim of this study was to study the effectiveness of two hydroalcoholic plant extracts on the mortality of the isolated Sitophilus zeamais and present in a stored maize dough and also the physical and physiological quality of the maize seeds treated with these extracts for six months storage, in type pet packaging in laboratory conditions without temperature and relative humidity control. The repellence, attractiveness and mortality of Sitophilus zeamais in maize grains treated with powders and hydroalcoholic extracts of Piper nigrum L. (black pepper) and Annona squamosa L . (sugar apple) were evaluated in laboratory. During storage, every 45 days, the infestation, loss of weight, moisture contents, germination and vigor of the maize were determined. The delineation was completely randomized and the treatments arranged in a factorial design, whose quantitative factors were revealed by regression of the variance analysis. According to obtained data it was concluded that the plant extracts used were efficient in repellence and mortality of the pest insect, with the best control for the extract of Annona squamosa L. at this stage of the experiment. In storage the percentage of the maize infestation decreased with the increasing dose and the germination presented to the extract of Piper nigrum L. 92.21% and to Annona squamosa L. 91.15%. 5 and 11 mL doses were the ones that best controlled the Sitophilus zeamais for both extracts. At the end of storage the black pepper extract was better than the sugar apple one in all vigor tests.