Studies on Seasonal Incidence and Evaluation of Bio-rational Insecticides Against Maize Stem Borers

Abstract

The investigation was carried out to study the distribution pattern and effective management of maize stem borers in a randomized block design with three replications during kharif, 2016 and Kharif, 2017 at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut. During the crop season, nine insect species and two natural enemies encountered on maize at different crop growth stages. Among these, Maize stem borer were recorded as severe pest and Pink stem borer were recorded as moderate pest. The other insect pests recorded on the crop were of less importance and extent of their economic damage was lower. The seasonal incidence of maize stem borer started from first week of July and reached its peak during third week of August during both the years. The seasonal incidence of pink stem borer started from first week of July and reached its peak during third week of August during both the years. The correlation indicated a positive correlation of maize stem borer with minimum temperature, relative humidity and rainfall while, negative correlation with maximum temperature. In case of pink stem borer incidence indicated a positive correlation with maximum and minimum temperature, relative humidity while, negative correlation with rainfall. The crop sown on 20th June has recorded the maximum infestation of maize stem borers (24.14 and 25.83 per cent), 5th August (22.80 and 23.12 per cent), 20th July (13.66 and 14.90 per cent) and 5th July (12.81and 13.74 per cent), respectively. The early and late sown crops received higher infestation and mid sown crops received lower infestation during both the years. Efficacy of different treatments viz Spinosad 45% S.C. @ 200 ml/ha, Emamectin benzoate 5 SG @ 200g/ha, Chlorantraniliprole 18.5 SC @ 150ml/ha, Carbofuran 3G @ 20 kg/ha, Neem oil @ 3.0 lit/ha, Bacillus thuringiensis @ 1.0 kg/ha, Metarhizium anisopliae @ 2.5 kg/ha, Beauveria bassiana @ 2.5 kg/ha and Mahua oil @ 2.0 ml/lit against maize stem borers revealed that Spinosad was most effective in reducing the infestation of maize stem borers followed by Emamectin benzoate. The highest yield was recorded from Spinosad where as the highest cost benefit ratio was obtained from Emamectin benzoate.