A study was conducted to determine the survival rate, fertility, and the parasite-host relationship of Eretmocerus debachi Rose and Rosen that parasite Parabemisia myricae (Kuwana) in a climate chamber at 25 +/- 1-degree-C. E. debachi propagated parthogenetically and no males were observed in the experiments. The parasitoid started to lay eggs immediately after hatching with a maximum of 16.6 eggs per day. The first mortality occurred 1 day after hatching and then the survival rate strongly dropped to zero. The intrinsic rate of increase (r(m)), calculated from a fecundity table valued 0.198, the net reproductive rate R0 and the generation T0 were computed as 45.23 females/female and 19.26 days, respectively. Second instar nymphs of P. myricae were preferred as hosts for parasitization in a choice and a no-choice test. A high mortality due to host-feeding was observed and the preferred stage for host-feeding was the first instar nymph in the choice and the no-choice test. The numerical response revealed an increasing parasitization with increasing host density, no matter whether the parasitoid was exposed for 1 or 3 days to the hosts. The maximum number were 52.8 parasitized instars per E. debachi female at a host density of 150 individuals. Only a slight increase of host-feeding was observed for host densities between five and 50 individuals in the studies of the functional response. A high mortality due to host-feeding occurred at a host density of 150 individuals and a 3 days exposure period averaging 32.3 individuals, which was significant higher compared to the 1-day exposure period (15.5 individuals).