Effect of Temperature on Biological Characteristics and Population Growth Parameters of Diaeretiella rapae, Parasitoid of Russian Wheat Aphid, Diuraphis noxia

Biological characteristics and population growth parameters of Diaeretiella rapae (Hym.: Braconidae) on Russian wheat aphid, Diuraphis noxia (Hem.: Aphididae) were investigated at five constant temperatures (10, 15, 20, 25 and 27.5 ?C), 60±5% RH and a photoperiodicity of 16:8 h (Light:Dark). Developmental period of immature stages of D. rapae was the lowest at 25 ?C (11.23±0.144 days) and highest at 10 °C (33.297±0.183 days). The highest valuesfor the of intrinsic vs finite rate of increase were obtained 0.189±0.003 day-1 and 1.208±0.003 days, at 20 °C, respectively. The developmental threshold of D. rapae using linear regression and Ikemoto-Takai linear models were estimated 2.975 and 2.44 °C, while thermal constants being estimated 250 and 260.1 degree-days, respectively. The Briere 2 model was accepted for success to satisfy criteria of goodness-of-fit (R2adi, SSE and AIC) and estimable temperature threshold parameters recommended for the description of temperature-dependent development of D. rapae. The highest adult female and male longevity of D. rapae were observed to be at 10 ?C. The maximum fecundity (numbers of mummies produced) of D. rapae was recorded as 57.1±1.7 at 10 ?C. The female offspring produced, decreased with increasing temperature. The results finaly revealed that optimal temperature for growth population of D. rapae is 20 °C.