Control del Sitophilus zeamais Motschulsky en almacén con aplicación de Clorpirifos Metil y Deltametrina y su efecto en la calidad de semilla de maíz

Abstract

Control of stored sitophilus zeamais Motschulsky with Clorpyrifos metil and Deltametrina, and its effect in corn seed quality. In this work, 4 concentrations of Clorpirifos metil and 4 of Deltametrina were evaluated, alone and in a mixture with Captan, attempting to control Sitophilus zeamais, deter mining the persistence of each insecticide through samplings every 30 days by a period of 210 days, as well as the phytotoxicity in the quality of maize seed of floury characteristics, with and without insect infestation. Probit analyses were performed with insecticides, alone and in mixture, and also for the quality of the seeds, the parameters were evaluated under a divided plot design. The main plot represented storage time and the small plot represented treatments (products and dosage). A Duncan test of average comparison at 0.5 was made, whereas the standard germination and accelerated aging transformed by means of arc sine at 0.05%). For the case of Clorpirifos metil, a concentration of 1.5 to 2 ppm protected the maize seed o the Sitophilus zeamais attack for 60 days, from 3 to 4 ppm for 90 days, fron 6 to 8 ppm for 150 days and from 12 to 16 ppm up to 210 days with 100 % of control. Regarding Deltametrina it was found that concentration of 2 to 4 ppm protects the maize seed of damage of the weevil of maize for 60 days, at 8 ppm for 150 days and at 16 ppm up to 210 days, with 100 % of control. The bioassay analyses indicated for both insecticides a degradation of the products as the time elapsed. The concentrations did not cause phytotoxicity effects and therefore they did not affect the germination or the vigor through the storage time. No effects of synergism or antagonism in the insecticide and fungicide mixture were detected. In the standard germination and accelerated aging tests, with and without insects, the treatments with Clorpirifos metil obtained a smaller answer in germination, lenght of plumule and radicula with respect to those containing Deltametrina; but without being statistically different.