Occurrence and damage: southern mustard mosaic virus was first reported by Smith and Markham in 1944, and occurred on the southern mustard Arabis.hirsuta in England. After 1960s, it was reported on Trifolium pratense in Europe, but less on other leguminous crops. Transmission method: South mustard mosaic virus is mainly transmitted by vector nematodes in the field, but also by mechanical friction inoculation, grafting, asexual propagation materials and seeds. The virus does not spread through contact between plants. Vector: A variety of nematodes can spread southern mustard mosaic virus, including Xiphinema.bakeri, Xiphinema.coxi of Kirks and Xiphinema.diversicaudatum of Schizocephala. It's mainly Nematodes fischeri. Seedling-borne plants: 2 1 species of plants in 14 family can spread mustard mosaic virus through seeds. Including beta vulgaris (13%), capsella bursa-pastoris (4.4% ~ 23.7%), Chenopodium.album(8.0%%), fragaria ananassa (2.5% ~/kloc). Soybean Glycine. Max (2.1%~ 20%), hops Humulus.lupulus( 12%), lettuce Lactuca. Spain (60% ~100%), and LYSIMACHIA. Lycopersicon esculentum (1.7%), Myosotis arvensis (19.9% ~ 95.4%), Nicotiana Cleveland II (35.3%), Petunia.hybrida(2.7%～20.0% Petunia.violaceae(20%～37%% ~ 37%), Plantago.major(5.7%～28.5%% ~ 28.5%), Poa annua (4%) and Polygonum hydropiper (21%~/). Edible rhubarb rheum rhaponticum (10% ~ 24%), Rosa.canina(3.8%%), Rosa rugosa (1.8%), Senecio.vulgaris(2.2%%) and Stellaria.