In this study the viruses occurring on papaya, bell pepper and chili in Okinawa and Shanghai were examined. Papaya leaf-distortion mosaic virus (PLDMV), which has been reported in Okinawa, and papaya ringspot virus P strain (PRSV-P), which was discovered on Miyako Island in 1991, belong to the potyvirus group and induce the development of similar symptoms on papaya. Since the two diseases cannot be distinguished from their symptoms, a field survey system using a very sensitive ELISA (enzyme-linked immuno-sorbent assay) was developed to enable the detection of theses viruses in crude extracts from infected papaya leaf at dilutions of 1000. Field survey using this system revealed the occurrence of PRSV-P on Ishigaki Island in addition to PLDMV although the frequency of occurrence of PRSV-P was low. The occurrence of virus diseases of bell pepper and chili in Shanghai was also investigated. Almost all the bell pepper plants were infected with viruses and showed more severe symptoms than those of chili. Electron microscopic observation, serological tests and sapinoculation tests revealed a wide distribution of the pepper strain of tobacco mosaic virus and cucumber mosaic virus throughout Shanghai, suggesting the occurrence of a filamentous virus.