Biology, feeding potential and functional response of Chrysoperla zastrowisillemi to cotton aphid, Aphis gossypii glover

Abstract

Biology, feeding potential and functional response of Chrysoperla zastrowisillemi to cotton aphid, Aphis gossypii Glover was studied in the laboratory at 25 ± 0.5 °C, 70 ± 5% RH and 12L:12D photoperiod. The study reveal that the incubation, total larval, pre pupal and pupal period of C. zastrowisillemi was 2.60, 11.62, 1.10 and 8.30 days, respectively. Pre oviposition, oviposition and post oviposition period of C. zastrowisillemi was 3.60, 24.70 and 7.80 days, respectively and each female laid an average of 398.9 eggs. On an average 1st,2nd and 3rd instars of C. zastrowisillemi consumed 30.46,98.7 and 301.7 aphids and total consumption during life cycle was 431.06 aphids/ predator. All the three larval stages of the predator exhibited Type II functional response to the aphid. Based on Rogers’s random predator equation the predator’s attack rate was lowest (0.089) in the firstinstar and highest (0.140) in the 3rd instar. Handling times of 1st, 2nd and 3rd instar was 1.767, 0.367 and 0.269h, respectively. Functional response parameters indicate that attack rate increased and handling time decreased with the advancement of the predator stage. Third instar larvae were the most voracious feeders and could be crucial for the biological control of the cotton aphid.