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-cho...