The isolate 85-1 was propagated on Datura stramonium and purified by PEG precipitation, two cycles of differential centri-fugation and sucrose density gradient centrifugation. The virus yield was 0.1 mg/ kg of fresh plant material. 分离物85-1在曼陀罗上繁殖,经PEG沉淀,两次差速离心和蔗糖梯度离心后的得毒率为0.1mg/kg材料。