Repellent and insecticide activity of leaves, flowers and extracts of African tulip tree (Spathodea campanulata B.), in stored grain weevils (Sitophilus zeamais M.)

Abstract

The maize weevil (Sitophilus zeamais Motsch. Coleóptera: Curculionidae), is a one of the main pest of the corn during postharvest. The annual loss of cereal crops during postharvest are results of insect damage, microbial degradation and others factors, the estimate between 10 to 25% of yield global loss. Traditionally the control of these pests is with chemical insecticides, that is not appropriate management, produces environmental problems and food residual insecticide. One alternative is to use natural insecticides that are friendlier to the environment and are more feasible to make in the field. Between the naturals products are substances from: nicotine, natural pyrethrum, neem (azaradichtina) and the African tulip leaves and flowers (S. campanulata B.), in the same way the respective extracts. These components of the tree could be an alternative to postharvest cereals pest like the maize weevil (S. zeamais). In this research we conducted assays to determinate insecticide and repellent activity of African tulip leaves, flowers and extracts respectively in a camera with wind channel in the Chemistry-Ecology Laboratory of ECOSUR, Tapachula Chiapas, Mexico. The results obtained showed statistically the insecticide and repellent effect of flowers and leaves on the maize weevil to 2 g/200 g of corn and the main activity were to 2 and 17 hours after of the application. The main insecticide extract effects were with flowers extract to 2.0 and 1.5 mg/ml solution after 12 hours of the application.