IN VITRO STUDIES ON IMPACT OF CADMIUM AND NICKEL ON GENERATIONS OF TOBACCO CATERPILLAR (Spodoptera litura Fab.)
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Date
2013
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ABSTRACT
The present investigations entitled “In vitro Studies on Impact of Cadmium and Nickel on Generations of Tobacco Caterpillar (Spodoptera litura Fab.)” was carried out during 2012-2013 in the Department of Environmental Science, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan. The main aim of this investigation was to find out the impact of heavy metals viz., Cd and Ni on generations of Tobacco Caterpillar (Spodoptera litura F.). Among all the treatments,maximum fecundity (766.56 eggs/ female), fertility (85.25% ), incubation period(3 days), larval period (17.06 days),pupal period (8.56 days), total developmental period(28.72 days), third instar larval survival was 100 per cent whereas sixth instar larval survival was 73.20 per cent, pupation (100%, adult emergence (97.78%), adult male longevity ( 8.78 days) ,adult female longevity (5.33 days), growth rate (GR) for second instar was 0.105 and increased to 0.814 in sixth instar, consumption index (CI) for second instar was 0.396 and increased to 2.055 for sixth instar, approximate digestibility(AD) for second instar was 71.62 per cent and decreased to 27.74 pe cent in sixth instar, efficiency of conversion of ingested food (ECI) for second instar was 36.32 per cent and decreased to 17.66 per cent for sixth instar, efficiency of conversion digested food (ECD) for second instar 51.66 per cent and increased to 68.29 per cent for sixth instar was recorded with artificial diet impregnated with 1 mg Cd/kg while 1 mg Ni/kg registered 767.22 eggs/ female, fertility (85.57% ), incubation period (3days), larval period(17.04 days), pupal period (8.56 days), total developmental period (28.70 days), third instar larval survival was 100per cent and sixth instar larval survival was 75.07per cent, pupation (100%), adult emergence (97.78%), adult male longevity ( 8.78 days) ,adult female longevity (5.67 days), GR for second instar was 0.106 and in sixth instar increased to 0.815, CI for second instar was 0.400 and for sixth instar increased to 2.061, AD for second was 71.53 per cent and decreased to 27.81 per cent for sixth instar, ECI for second instar was 36.36 per cent and for sixth instar decreased to17.59 per cent, ECD for second instar was 51.69 per cent was increased to 68.41per cent for sixth instar. Artifical diet treated with 40 mg Cd/kg resulted minimum fecundity (466 eggs/ female), fertility (72.53), incubation period (3.94 days), larval period(23.39 days), pupal period(6.44 days), total developmental period (33.97days), third instar larval survival 75 per cent whereas for sixth instar larval survival was 33.33 per cent, pupation (64.44%), adult emergence (63.89%), adult male longevity ( 5.33 days), adult female longevity (3.67 days) , GR for second instar was 0.130 and increased to 0.714 for sixth instar, CI for second instar was 0.204 and increased to 1.179 in sixth instar, AD for second instar was 65.75 and decreased to 24.50 per cent in sixth instar, ECI for second instar was 32.98 and decreased to13.74 per cent in sixth instar, ECD for second instar was 46.15 and increased to 55.65 per cent in sixth instar. Artifical diet treated with 40 mg Ni/kg resulted minimum fecundity (472.56 eggs/ female), fertility (73.12%), incubation period (4 days), larval period (23.05days), pupal period (6.67 days), total developmental period (33.64 days), third instar larval survival was 80 per cent whereas sixth instar larval survival was 33.33 per cent, pupation (71.11%), adult emergence (67.59%), adult male longevity ( 5.67 days), adult female longevity (4.0 days) , GR for second instar was 0.131 and increased to 0.722 in sixth instar, CI for second instar was 0.212 and increased to1.188 in sixth instar, AD for second instar was 66.06 and decreased to 24.93 per cent in sixth instar, ECI for second instar was 33.23 and decreased to 14.11 per cent in sixth instar, ECD for second instar was 46.75 and increased to 56.52 per cent in sixth instar. Hence, it can be concluded that growth and development of S. litura F was dose dependent. The higher doses of cadmium and nickel in the artificial diet increased generation time, whereas, lower doses shortened the generation time. So accumulation of cadmium and nickel in agroecosystem might influence the growth and development of Spodoptera litura F. through host plants to some extent.