TEMPERATURE EFFECT ON DEVELOPMENTAL, RATE LONGEVITY AND PARASITISM OF Diaeretiella rapae (M'INTOSH) (HYMENOPTERA- APHELINIDAE)

Temperature- dependent, biological aspects longevity and parasitism of the parasitoid diaeretiella rapae (m'intosh) was measured at three constant temperatures (15, 25 and 30 °c) using brevicoryne brassicae (l.) . the threshold (t0) and thermal units (dd's) of different stages of d. rapae at different temperatures, 15, 25 and 30 °c., were studied. the rate of development of all stages increased as the temperature increase from 15 to 30 °c. the mean of thermal units recorded 117.9, 88.84 and 222.45 dds for egg-mummy period, mummy- adult period and adult longevity respectively. also, the threshold development estimated as 2.4, 1.6 and 3.4 °c for egg- mummy period, mummy- adult period and adult longevity respectively.