Seed Quality of Maize, Treated with Extracts from Leaves of Melia azedarach L. against Sitophilus zeamais Motschulsky in Storage

Abstract

The maize weevil (Sitophilus zeamais Motschulsky) is considered the most important pest of corn in storage in Mexico, and comes to cause losses of up to 30 and 40 % of production during storage. The use of chlorine and phosphorus for control may cause damage to the environment human and animal health, so that, alternative treatments are needed. The aim of this study was to determine the insecticidal effect of extracts of lilac leaves (Melia azedarach L.) on the maize weevil, S. zeamais and its response through the time in the physiological quality of stored corn seeds. Corn seed was used AN-447 stored for 80 d. The leaf extracts of M. azedarach were applied to stored corn seed at 100, 75, 50 and 25 %. To evaluate the effect of extracts on the physiological quality of seed, samples were taken every 40 d and the ability of germination and vigor (mean length of plumule and radicle) was determined. The insecticidal effect of the extracts was very low, lower than 16 % mortality during the first 24 h after infection. But after 7 d of storage, the extracts caused a mortality of S. zeamais of 90 %, with fresh leaf extract in methanol at 99.80 % with 100 % of the concentration. Leaf extracts of M. azedarach did not damage the physiological quality and seed vigor during 80 d of storage.