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ThesisItem Open Access Studies on host preference, olfactory and functional response of generalist predator, Eocanthecona furcellata (Wolff.)(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-10) Chaudhary, Devyani; Maurya, R.P.The present investigations were carried out at Biocontrol Laboratory, Department of Entomology, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar during 2018-2020. Results on host preference of 2nd nymphal instar, 3rd nymphal instar, 4th nymphal instar, 5th nymphal instar and adult predatory bug of Eocanthecona furcellata revealed that Spodoptera litura followed by Corcyra cephalonica and Spilarctia obliqua were found as preferred host. The percent preference of second, third, fourth, fifth nymphal instars and adult predatory bug were 41.67, 50.00, 58.33, 75.00, 83.00 percent on S. litura, respectively. Results of the host selection by olfactory response revealed that the adult predatory bug preferred odour cell with larval extract of S. litura (48%), followed by larval extract of S. obliqua (32%), C. cephalonica (14%) and control odour cell (8%). The predatory bug was able to complete its immature life in five nymphal instars on live and freeze killed larvae of S. litura and C. cephalonica. The total nymphal period varied from 17.33±0.88 to 21.33±0.33 days. Total life cycle ranged from 31.33±0.33 to 36.33±0.66 days and number of eggs laid varied from 25.33±0.88 to 67±1.15. The consumption rate of nymphal instars ranged from 34.16±1.27 to 51±4.93 percent, 45.83±3 to 68.89±1.11 percent, 59.04±0.95 to 71.33±5.81 percent, 55.83 ± 4.40 to 81.11±1.82 percent. The consumption rate of adult predatory bug on different factitious hosts varied from 75.8±0.54 to 84.79±1.18 percent. The mean consumption rate of different stages of predatory bug ranged from 45.86±0.52 to 59.27±1.98 percent on live and freeze killed larvae of S. litura and C. cephalonica. The results of the study of functional response of fourth, fifth nymphal instars and male and female predatory bug on four, six, twelve days old larvae of S. litura demonstrated a type II functional response at different prey densities. The estimated parameters of attack rate of fourth, fifth nymphal instars ranged from 0.942±0.04 to 1.506±0.199, 0.969±0.017 to 1.161±0.074 prey/ day with a handling time of 0.075±0.017 to 0.58±0.087, 0.027±0.007 to 0.443±0.066 days at different prey densities. The parameters of attack rate estimated for male predatory bug on four, six, twelve days old larvae of S. litura were 0.975±0.014, 0.901±0.033, 0.844±0.092 whereas, for female predatory bug, attack rate was estimated as 0.982±0.015, 0.927±0.033, 0.903±0.032 prey / day, respectively. The handling time of male and female predatory bug varied from 0.024±0.006 to 0.204±0.04 and 0.013±0.007 to 0.099±0.014 days, repectively. The study suggested that the predatory bug, E. furcellata can be mass reared in laboratory conditions using larvae of S. litura and C. cephalonica and could be exploited in various IPM programmes.
