Bioefficacy of insecticides and bio-pesticides against yellow stem borer, scirpophaga incertulus (walk.) and their effect on spiders in rice crop

Abstract

All the treatments tested for the management of yellow stem borer, Scirpophaga incertulus (Walk.) had the comparable lower number of dead hearts and white ears than untreated control. Fipronil 5 SC was best with final infestation of 1.9 % and 45.83 q/ha yield followed by cartap hydrochloride 50 SP, triazophos 40 EC, cartap hydrochloride 4G, lambda cyhalothrin 5 EC, endosulfan 35 EC, Bt and neemarin which gave 44.96, 43.37, 42.49, 40.13, 39.85, 39.07 and 38.78 q/ha yield, respectively. Maximum numbers of predatory spiders were recorded in control plot and it was 3.26 / hill. Among the different treatments the maximum number of spiders was found in cartap hydrochloride 4 G followed by fipronil 5 SC as 1.66 and 1.53 / hill, respectively.. Bioefficacy of insecticides and bio-pesticides against yellow stem borer, Scirpophaga incertulus (walk.) and their effect on spiders in rice crop. South Asian J. Food Technol. Environ. 1(2): 179-183. Rice (Oryza sativa L.) is one of the most important cereal crops of India and is a staple food of more than 65 % of its population. The rice crop is subjected to sustain a considerable damage by a number of insect pests, among them yellow stem borer, Scirpophaga incerulas (Walk.) is the principle devastators, which is responsible for economic crop losses under local conditions (Kumar et al., 2012). This insect attacks the crop from the seedling stage to the harvesting stage and thus causes complete loss of affected tillers. Dead hearts are produced when the insect attacks at vegetative stage while white heads occur when the stem borer attack at time of heading. Chemical insecticides are still effective method to control insect pests particularly in the rice crop. The indiscriminate use of chemical insecticides can be environmentally disruptive and can result in the accumulation of residues in the harvested produce. Dodan and Lal (1999); Kaul and Sharma (1999) and Rath (1999 & 2001). The use of conventional insecticides causes sudden decrease in the number of natural enemies also. Keeping in view the importance of rice crop, the present study was undertaken and results thus obtained are presented herein. Material and Method The field trial was conducted 2010 at Crop Research Centre of the S.V.P.U.A. &T., Meerut, laid in R.B.D. with nine treatments and 3 replications. The treatments were T1, triazophos 40 EC @ 0.75 lit./ha, T2, cartap hydrochloride 4G @ 18.75 kg/ha, T3, lambda-cyhalothrin 5 EC @ 0.625 lit/ha, T4, fipronil 5 EC @ 18.75 kg/ha, T5, endosulfan 35 EC @ 1.5 lit/ha., T6, cartap hydrochloride 50SP @ 1.0 kg/ha., T7, neemarin @ 1.5 lit.,/ha., T8, Bacillus thuringiensis var, kurstaki @ 1.5 kg/ha. and T9, untreated control. All the treatments were applied twice, first at the 50 days and second at 75 days after transplanting with hand operated knapsack sprayer, only water was sprayed in untreated control plot, the spray volume used for foliar application of insecticide was 600 litre\ha. During spraying due care was taken to prevent insecticides drift and granular insecticide was applied after mixing in 10 Kg sand/acre. The observations on dead hearts and white ear formation due to yellow stem borer were taken on five randomly selected hills / plot, before 1 day and after 3, 7, 14 and 20 one days of application. The percentage of dead hearts / white ears was worked out. Grain yield / plot was also recorded at harvest and it was converted in to quintal / ha. for analysis and comparison. The economics of each treatment was also worked out on the basis of cost benefit ratio. Results and Discussion All the treatments were significantly effective in reducing the infestation of rice yellow stem borer (YSB) and thus, reducing the formation of dead heart and white ear significantly as compared to the control (Table 1).