Browsing by Author "Uttamrao, Shinde Chandrashekhar"

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    Biology and Feeding Potential of Pseudaspidimerus trinotatus (Thunberg) (Coleoptera : Coccinellidae) and Chrysoperla carnea (Stephens) (Neuroptera : Chrysopidae) on bean aphid, Aphis craccivora Koch
    (Agricultural Entomology Department, N. M. College of Agriculture, Gujarat Agricultural University, 2008-11) Uttamrao, Shinde Chandrashekhar; Patel, M. B
    Investigation on biology and feeding potential of Pse udaspidimerlls trinotafus (Thunberg) and ChrysoperJa carnea (Stephens) on bean aphid, Aphis craccivora Koch were carried out in the Bio-control Laboratory, Department of Agricultural Entomology, N. M, College of Agriculture, Navsari Agricultural University, Navsari during the year December 2006 to February 2007 and December 2007 to February 2008, The laboratory experiment was conducted against larvae of C. carnea to evaluate the relative toxicity of different insecticides during February 2008. Studies on the biology P. trinotatus on A. craccivora indicated that the lady bird beetle did not lay eggs on leaves under the laboratory condition when fed on A. craccivora , However, they were laid on under surface of the lid of the container near to the grooves. The eggs were spindle shaped and pale yellow in colour. The average incubation period and hatching percentage were 4,92 Jl6stract ±0.778 days and 87 .93 ± 2.589 per cent, respectively. The larvae passed through four instars. The average developmental period of first, second, third and fourth instar larva was 1.52 ± 0.505, 2.78 ± 0.790, 2.44 ± 0.501 and 3.40 ± 0.495 days, respectively. The average total larval period was 10. I 4 ± 1.340 days whi Ie; the prepupal and pupal period were 1.50 ± 0.505 and 7.82 ± 1.335 days, respectively. The average pre-oviposition, oviposition and post-oviposition period were 7.54 ± 1.249, 17 .50 ± 2.140 and 5.76 ± 0.771 days, respectively. The average fecundity of the female was 142.76 ± 17.75 eggs. The average longevity of male and female was 26.40 ± 3.017 and 30.80 ± 2.515 days, respectively. Total life cycle occupied on an average of 50.78 ± 3.495 days by male and 55.18 ± 3.348 days by female . The measurements of various stages of P. trinotatlls were also recorded . Studies on feeding potential of P. trinotatlls revealed that the average consumption of A. craccivora by first , second, third and fourth instar larva, male, and female adults were 3.34 ± 1.002, 7.70 ± 2.159, 12.70 ± 2.772, 34.70 ± 5.203, 91.76 ± 10 .85 and 134.74 ± 14.17 aphids, respecti vely. The predator consumed on an average 58.40 ± 7.130 aphids during its development. During entire life period of P. trinotatus consumed on an average 171 .69 ± 13.17 aphids when reared on A. craccivora. Biology of C. carnea on A. craccivora revealed that the freshly laid eggs were stalked, oval and pale green in colour, which turned to dark grey prior to hatching . The average incubation period was 4.46 ± 0 .503 days while the hatching percentage was 79.87 ± 2.822 . The larva passed through three jl6stract distinct instars. The mean duration of first, second and third instar larva was 2.52 ± 0.505, 3.14 ± 0.729 and 3.50 ± 0.580 days~ respectively. The average total larval period was 9.16 ± 0.997 days when fed on A. craccivora. The average prepupal and pupal period were 1.00 ± 0.00 and 7.620 ± 0.945 days, respectively. Mean preoviposition, oviposition and post oviposition period was 4.92 ± 0.752, 23.84 ± 3.454 and 7.58 ± 1.032 days, respectively. The average egg producing capacity of gravid female was found to be 509.96 ± 77.43. An average longevity of male and female was 26.58 ± 3.855 and 36.34 ± 3.311 days, respectively. Total life cycle occupied was of 50.25 ± 4.389 days in male and 58.58 ± 3.357 days in female under the laboratory condition. The morhpometrics of various stages of C. carnea were also recorded during the present investigation. Laboratory studies on the feeding potential of C. carnea on A. craccivora indicated that the larvae of first, second and third instar consumed 33.68 ± 7.58, 86.88 ± 18.17 and 276.8 ± 37.90 aphids, respectively. A single predatory larva consumed on an average 397.32 ± 38.86 aphids during its developmental period. The result of the study on relative toxicity of different insecticides revealed that the treatment of profenophos 40 per cent + cypermethrin 4 per cent (Polytrin - C 0.044 %) and acetamiprid 0.004 per cent proved to be most toxic to the larva of C. carnea. Further, methyl-O-demeton 0.05 per cent, thiamethoxam 0.005 per cent, endosulfan 0.075 per cent and imidacloprid 0.005 per cent were found moderately toxic to the larva. However, dimethoate 0.03 per cent found safer to the larvae of C. carnea.