Evaluation of some important insecticides against Chilo partellus (Swinhoe) and Marasmia trapezalis (Guen.) infesting maize crop

Field efficacy of eight insecticides, viz., methyl-o-demelon, chlorpyriphos, fen valerate, decamethrin, cypermethrin, mavric, endosulfan and permethrin was studied against Marasmia trapezalis Guen. and Chilo partellus (Swinhoe) infesting maize. Observations showed that in the untreated control, the leaves infested by the leaf roller, M. trapezalis ranged from 9.2 to 13.6 per cent, while the plants infested by stem borer (C. partellus) varied from 26.0 to 33.9 per cent. As regards the effectiveness of insecticides against M. trapezalis, mavric (0.005%) was found to be best followed by permethrin (0.005%) and endosulfan (0.07%). However, endosulfan proved to be superior against C. partellus over the other insecticides. But, mavric and cypermethrin (0.005%) were statistically at par with endosulfan. The yield of grain and fodder was also as high as 41.64 and 133.25 q/ha, respectively in the case of endosulfan.