Establishment of Panonychus citri (McGREGOR) population on field-grown soybeans and kudzu-vines was observed in late autumn at Akitsu in Hiroshima Pref. Development and reproduction of five P. citri populations collected from different localities in Japan were examined on three leguminous plant species, viz. kidney bean, kudzu-vine and white clover, and citrus. Four populations collected from citrus (Hiratsuka, Shimizu and Akitsu-citrus) and soybean (Akitsu-bean) were a non-diapause strain. The other was a diapause strain collected from Japanese pear (Izumo). In all the five populations, successful development and eproduction were observed on kidney bean and kudzu-vine, though total egg production was about one half that on citrus. On white clover, individuals from the Hiratsuka and Shimizu populations developed to the adult but the total egg production was much smaller than that on kidney bean and kudzu-vine. The Izumo population did not reach adulthood on clover. Individuals from the Akitsu-bean population which had been reared on kidney bean for 9 months developed to the adult and the females oviposited on citrus, as did the Akitsu-citrus population. These results suggest that P. citri can successfully reproduce on certain leguminous plants such as kidney bean, kudzu-vine and soybean, and these herbaceous plants may be important for the maintenance of the mite populations when main tree hosts such as Japanese pear and citrus have deteriorated.