Host stage preference and effect of temperature on functional response of Aphidius matricariae (Hym.: Aphididae) on common wheat aphid

In this research, host stage preference of parasitoid wasp, Aphidius matricariae Haliday in choice and no-choice tests and functional response of the parasitoid were investigated on common wheat aphid, Schizaphis graminum Rondani on the Alvand cultivar in laboratory conditions at 20, 25 and 30 °C, RH 70 ±10 % and a photoperiod of 16 h L : 8 h D. The maximum mean parasitisms in choice and no-choice tests was on third instar nymph of the aphid and were 5.1 ± 0.43 and 10.3 ± 0.61 nymphs, respectively and the minimum mean parasitism was achieved on first instar nymph. The results of logistic regression showed that functional response of the parasitoid to different densities of the aphid was type II at 20, 25 and 30 °C. By using Rogers equation, attack rate and handling time were estimated. The maximum attack rate and minimum handling time were obtained at 20 °C.