Efficiency and pradatory of Hippodamia variegata (Goez) feeding on pomegranate green aphid, Aphis punicae Pass. under laboratory conditions

The functional response and predation rate of Hippodamia variegata (Goeze)(Col.: Coccinellidae) were studied under laboratory conditions at 25 and 27.5oC, 65 ± 5 RH and a photoperiod of 16:8 (L:D). In order to study the predation rate, newly first instar larvae were chosen and each age stage were fed by three and four instars of pomegranate green aphid, Aphis punicae (Hem.: Aphididae). According to the results, predation rate at 25 and 27.5°C were 11.4 and 10.3% for larval stage, and 86.8 and 89.7 % for female adult stage, respectively. The consumption value in females compared to males is 1.5 times. The net predation rate (C0) at 25 and 27.5 °C were 1725.14 and 1870 three and four instars of pomegranate green aphid respectively. The result showed that all age stages of the predator at 25 and 27.5 oC exhibited type II functional response. Thus, based on the searching efficiency at 25°C, 3th and 4th larval instars and at 27.5°C 4nd larval instar and adults of H. variegate are the most effective as predators on A. punicae. So in both temperatures, fourth instar larvae showed a better searching efficiency. The results indicated that the H. variegata may be a useful candidate for the biological control of A. punacae in pomegranate gardens.