Biology of two spotted mite Tetranychus Urticae koch on okra genotypes Nain Jitender*, Singh Ram, Rathee Mandeep, Gulati Rachna Department of Entomology, CCS Haryana Agricultural University, Hisar, 125004, Haryana *Email: jitender12121984nain@gmail.com
Online published on 12 June, 2017. Abstract Biology of two spotted mite, Tetranychus urticae Koch was studied on seven okra genotypes, namely, HB-02-14-1-1, HB-02-17-1, HRB-107-4-1, HT-1-17-5, T-6-15-3-7, BB1 and standard check “Hisar Unnat”. HBT-6-15-3-7 was observed to be more preferred for egg laying (52.61 eggs/leaf disc) followed by Hisar Unnat (49.22) and BB1 (47.79), while other genotypes were less susceptible with less eggs. Longest incubation period was found on the least susceptible genotype HB-02-14-1-1 (4.57 days) and shortest was on highly susceptible genotype HBT-6-15-3-7 (3.16 days). Longest larval period was found on HBT6-15-3-7 (5.16 days) and shortest was found on HTB-1-17-5 (3.40 days). Longest nymphal period (4.81 days) was observed on moderately susceptible genotype (HTB-1-17-5) while shortest nymphal period was recorded on the least susceptible HB-02-17-1 (4.22 days). Shortest total life period was observed on the genotype HTB-1-17-5 (17.39 days), while in highly susceptible HBT-6-15-3-7 (21.19 days) the total life period was longest. Shortest oviposition period was observed on HB-02-14-1-1 (5.66 days) and longest on BB1 (8.61 days) and shortest longevity of female was found on genotype HB-02-14-1-1 (8.28 days) while it was the longest on HBT-6-15-3-7 (11.71days). Female to male ratio was found maximum on the moderately susceptible genotype HRB-107-4-1(4.3: 1) and minimum with the least susceptible genotypes HB-02-14-1-1 (2.4: 1). Top Keywords Tetranychus urticae, incubation period, oviposition period, longevity, sex ratio, susceptibility, oviposition preferences. Top |