Bioactivity of tepa (Laureliopsis philippiana (Looser) Shodde) powder to Sitophilus zeamaisMotschulsky control in laboratory.

Ana Ortiz U.1,Gonzalo Silva A.1*, Angelica Urbina P.1, Nelson Zapata S.M.1, Concepción Rodríguez M.2, Angel Lagunes T.2

The maize weevil (Sitophilus zeamais Motschulsky) is one of the most widespread pests and causes heavy losses of stored grain throughout the world. Control of this insect is primarily dependent upon continued applications of organophosphorus and pyrethroid insecticides and fumigants as phosphine but the increasing problems with current insecticides drive the need for research and to develop new control methods. The insecticidal effect of leaf powder of tepa, Laureliopsis philippiana (Looser) Shodde, was evaluated against maize weevil under laboratory conditions. The parameters evaluated were adult mortality and emergence, grain weight loss and germination, and residual, repellent and fumigant effect. The highest levels of insect mortality were registered with treatments at 1, 2, and 4%, with values from 94.7 to 100%. Also, it was obtained 0% of adult insect emergence with these concentrations. In all treatments grain weight was less than 5.8 g. Seed germination was not affected. The powder of L. philippiana exhibited repellent effect in all concentrations and did not show fumigant effect. Insecticidal effect of powder remained for 14 d. Finally, we concluded that powder of L. philippiana has great potential for controlling S. zeamais.

Keywords: Stored grains, botanical insecticides, maize weevil.
1Universidad de Concepción, Facultad de Agronomía, Av. Vicente Méndez 595, Casilla 537, Chillán, Chile. *Corresponding author (gosilva@udec.cl).
2Colegio de Postgraduados, Programa de Entomología y Acarología, km 36.5 Carretera México-Texcoco, CP 56230, Montecillo, Estado de México, México.