Identifying hosts: quinoa: within 7-10d after inoculation, inoculated leaves produce localized faded green spots, and systemic symptoms include mottling, parietal leaf bending, and stem tip necrosis. Amaranthus quinoa: localized fading green spots, mottling of leaves, twisting of terminal leaves, and finally causing apical necrosis. Cleveland smoke: localized necrotic ring spots, systemic necrotic spots on new leaves. In vitro stability: ① passivation temperature. 65℃. ② Dilution limit point. 10-4. ③ In vitro survival period. 5d (20℃). Serological detection: excellent immunogenicity of the virus. Take MI strain as antigen, immunize rabbits, inject 0.5~1.0mg of virus intramuscularly, ***3 or 4 times, 7~14d interval/times, make antiserum, potency 1/512~1/1024 (agar double diffusion). There was no serologic relationship with southern mustard mosaic, Italian chrysanthemum latent, cherry leafroll, grape fanleaf, peach cluster mosaic, hoverfly ringspot, strawberry latent ringspot, tobacco ringspot, and tomato black ring viruses. However, there is a weak relationship with Bulgarian grapevine latent virus. Evaluation of quarantine risk: The pathogen of this disease, Uryza sativa leaf mottle virus, can be transmitted over long distances through the propagation material of lingonberries and grapes, and can be expanded and spread by nematodes, constituting considerable economic losses. Although it has not yet occurred in the country, there have been records of imported plant propagation materials that can transmit the pathogen in the past, and the chances of invasion are high. Domestic hosts and vectors are available, with good conditions for survival and easy rooting and colonization. Jiliang (1980) in the evaluation of the risk, the risk value of 6 points, as a low-risk hazardous quarantine pests. Quarantine measures: The import must be approved by the plant quarantine organization above the province, and it is required to be accompanied by "Quarantine Certificate" of the exporting country to ensure that it does not carry this kind of virus. After the entry of the local plant quarantine institutions under the supervision of more than 1 year of fertility of the isolation test, confirmed disease-free, before being allowed to use for breeding or production planting.