Functional response of Encarsia formosa (Gahan) parasitizing castor whitefly, Trialeurodes ricini Misra (Hom., Aleyrodidae).
Laboratory experiments were conducted to measure the functional responses of Encarsia formosa parasitizing Trialeurodes ricini. Parasitoids were isolated singly for 24 h in 10-cm Petri dishes with 4, 8, 16, 32, 64 or 128 prepupal stages of T. ricini. Results showed a typical Type II response, with up to 12 prey attacked when 128 were provided. The rate of attack and handling time were 1.43 and 0.077 days, resp. Theoretically, one T. ricini prepupa could be parasitized by E. formosa every 111-115 min (0.077-0.080 days), and an adult E. formosa could parasitize a maximum of 13 T. ricini prepupae/day.