Propiedades insecticidas del polvo de Laurelia sempervirens L. para el control de Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Abstract

Sitophilus zeamais is a key pest of stored cereals. The insecticidal properties of Laurelia semper v irens powder against S. zeamais were assessed in laboratory. The variable evaluated were morta lity of adult insects by contact and fumigant toxicity, mortality of immature insects by contact toxicity, residual effect of powder stored under environmental or refrigerated conditions, adult insect em ergence (F1), repellency and weight reduction and ger mination of maize. The concentrations evaluated were 0, 0.25, 0.5, 1.0, 2.0 and 4.0% and the experimental design was completely randomly. In contact toxicity bioassay all treatments showed mortality over 90% while fumi gant activity did not exceed 40%. The F1 only was registered in treatment of 0.25% and control showing all other treatments 0%. In immature control bioassay all treatments exhibited statistical differences with control. The storage of powder under refrigerated cond itions not improved the resid ual effect. All concentrations of powder assessed showed repellence. Germination and grain weight loss of maize seeds not showed significant differences with control. We concluded that L. sempervirens has promissory perspectives to stored grain pests contr ol.