Grapevine fanleaf virus (GFLV) is a plant pathogenic virus of the family Secoviridae. It infects grapevines, causing chlorosis of the leaves and lowering the fruit quality. Because of its effect on grape yield, GFLV is a pathogen of commercial importance. It is transmitted via a nematode vector, Xiphinema index. This nematode acquires the virus through feeding on roots of an infected plant, and passes it on in the same manner.