The effects of three constant temperatures (20, 25, 30 + 1 degrees C) and two fluctating temperatures (25/35, 27/33 degrees C) on the preimaginal developmental time and the longevity of the parasitoid Eretmocerus debachi Rose and Rosen (Hym., Aphelinidae) that parasitized Parabemisia myricae (Kuwana) (Hem., Aleyrodidae) were studied in the laboratory. In addition, laboratory experiments were conducted to study the effects of different diets on the longevity of the parasitoid. The generation time and the number of generation in a year were evaluated in a semi-field experiment. The preimaginal developmental time decreased significantly with increase in temperature from 28.4 days at 20 degrees C to 12.0 days at 27/33 degrees C. Increasing temperature showed little effect on adult longevity, varying from 3.1 days at 20 degrees C to 3.7 days at 25 degrees C. Longevity was significantly shorter at the fluctuating temperatures (25/35 and 27/33 degrees C) compared to the constant temperatures. E. debachi herd on 10% saccharose solution lived significantly longer (3.4 days) than on any other five diets. Only slight differences were observed among honey dew, water or no diet, ranging from 1.2 to 1.6 days. In the semi-field experiment 13-14 generations in a year were observed. The shortest generation time valuing 14 days was observed during summer time at average daily temperatures between 25.1 and 28.9 degrees C. A generation time of 145 days occurred in winter (November-April) when the daily temperature averaged 10.8 degrees C. E. debachi hibernated in second P. myricae instars.