Population trend of corn leaf aphid Rhopalosiphum maidis. with different chemical doses in three maize varieties

Authors : Isma KHURSHID, Jabir ALAM, Asad ALI, Hidayat ULLAH, Abur RAQIB, Gul NAZ

Pages : 1-7

View : 7 | Download : 9

Publication Date : 2013-04-15

Article Type : Research Paper

Abstract :Field experiment was conducted to find out the comparative efficacy of different commercial insecticides for the control of aphids, Rhopalosiphum maidis Fitch Homoptera: Aphididae and to study the resistance level of the newly released maize variety Jalal to the farmers for general cultivation in comparison with the two commonly grown corn cultivars Azam and Sarhad white . Experiment was laid down in a randomized complete block design with three replications. The treatments included; seed dresser ImidaclopridTM , granular application CarbofuranTM and foliar spray MethamidophosTM , each in recommended and half of the recommended doses. Aphid’s population data were recorded on weekly intervals for each treatment upon the varieties. Seed dresser, granules application and foliar spray significantly reduced aphid infestation from 1st week to 4th week as compared to control. Recommended dose of all of the insecticides significantly minimized the aphid’s population as compared to half doses. The newly released cultivar ‘Jalal’ showed comparatively more resistance to the aphid’s infestation as compared to ‘Azam’ and ‘Sarhad White’ suggested that the old cultivars have almost lost their resistance against the available strains of aphids. Similarly recommended dose of seed dressing resulted in maximum grain yield 2841 kg ha-1 followed by the recommended dose of foliar spray, whereas; minimum grain yield 2678 kg ha-1 was recorded in control plots. Maize variety ‘Jalal’ produced higher grain yield 2857 kg ha-1 followed by ‘Azam’ 2818 kg ha-1 . Outcome of the experiment suggested that ‘Jalal’ is not only a productive variety but also proven tolerant to aphids compared to the existing two corn varieties Azam and Sarhad White . Thus these findings provided a tool to focus on the use of recommended doses of ImidaclopridTM as seed dresser with low toxicity and environmental safety for early protection, good plant vigor and greater yield. The same variety can be used in the development of potential hybrid or varieties breeding
Keywords : Aphids infestation, Pesticide application, Corn cultivars