Two generalist phytoseiid mites, Amblyseius eharai Amitai and Swirski and Euseius sojaensis（Ehara）（Acari: Phytoseiidae）, are useful biocontrol agents in citrus fields, and their reproduction is expected to be enhanced by supplying alternative foods. We reared phytoseiid mites on the pollen of six tree species and evaluated the effect on reproduction. The intrinsic rate of natural increase（r_m）of A. eharai was 0.179 to 0.216 when the pollen of Pinus thunbergii, Distylium racemosum, Camellia sinensis, or Morella rubra was provided, suggesting that these four types of pollen were suitable for the reproduction of A. eharai. When pollen from Citrus natsudaidai and Cryptomeria japonica was provided, r_m was lower（0.085, 0.082）but still positive, because the net reproduction rates（R₀）were lower and the mean generation times（T）were longer than with the above four pollen types. E. sojaensis had r_m of 0.166 to 0.196 when P. thunbergii, D. racemosum, C. sinensis, or M. rubra was provided, which appear to support E. sojaensis reproduction. However, with C. natsudaidai and C. japonica pollen, the R₀ was extremely low and the r_m was negative. Based on these results, the pollen of P. thunbergii, D. racemosum, C. sinensis, and M. rubra are suitable foods for the reproduction of these two species of generalist phytoseiid mites.