Abstract: The effects of Pandora delphacis infection on the net reproduction rate (R₀) and innate capacity for increase (r_m) of the green peach aphid, Myzus persicae were investigated. Seven day old nymphs inoculated with the fungal conidia at a dosage higher than LD₅₀ were maintained on the Chinese cabbage, Brassica olerracea, at temperatures of 10～30℃ and relative humidity (RH) of 74%～100%. The results indicated that number of nymphs produced by the treated aphids was significantly less than those produced in control, especially at higher temperatures (20～30℃) and RHs (95%～100%). Their r_m differed greatly among the temperatures tested, showing a parabolic curve with the peak at 25℃. No significant effect of RH on their r_m was detected. The inoculated aphids at 15～25℃ had an innate capacity for increase significantly smaller than those in control. These results suggested that P. delphacis be a potential microbial agent against the aphid.

Key words: Pandora delphacis, Myzus persicae, fecundity, innate capacity for increase, temperature, relative humidity