Studies on the population dynamics of aphid Lipaphis erysimi Kalt on Brassica genotypes and its management through biorational insecticides on Indian mustard Brassica juncea L

Abstract

The present investigations entitled Studies on the population dynamics of aphid (Lipaphis erysimi Kalt.) on Brassica genotypes and its management through biorational insecticides on Indian mustard, Brassica juncea L. were carried out at oilseed Farm, Kalyanpur, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur during Rabi 2018-19 and 2019-20. The incidence of mustard aphids was found variable on different Brassica spp. from 2nd to 12th SMW. The maximum population of mustard aphid (247.2 aphid 10 cm-1 central twig plant-1) was observed on genotype BSH-1 Brassica spp. during Rabi 2018-19, while during 2019-20, the maximum population of as (189.7 aphid 10 cm-1 central twig plant-1) was observed on genotype YST-151 of Brassica spp. The correlation matrix indicates the incidence of mustard aphid on BSH-1 was also found to be positively correlated with minimum temperature, maximum, minimum relative humidity and wind speed with r = 0.108, r = 0.405, r = 0.409 and r = 0.370, respectively, whereas, it was negatively correlated with maximum temperature, rainfall, and sunshine hours with r = -0.147, r = -0.030 and r = -0.296, respectively,. Similarly the incidence of mustard aphid on GSC-6 was positively correlated with maximum and minimum temperature and wind speed i.e. r = 0.229, r= 0.298 and r = 0.181, respectively, and negatively correlated with maximum and minimum relative humidity, rainfall and sunshine hours with r = -0.082, -0.046, -0.196 and -0.199, respectively, during both years. The sixty Brassica genotypes were screened against the mustard aphid (L. erysimi) under field conditions based on the Aphid Infestation Index ( 0-5 scale) twice at 50% flowering stage and second at the pod setting stage and found that the overall mean A.I.I. at flowering and pod setting stages varied from 0.4 to 4.6 in genotypes Kanti and NRCHB-101, respectively, in the first season newlineand 0.7 to 4.4 was found in genotypes Kanti and RGN-229 respectively, during the second season.