Molecular sampling of HSVd in grapevines in the environs of hop gardens was performed. Specific RT PCR primers were designed to unambiguously distinguish between HLVd and HSVd infections. These primers were used for detection and analysis of HSVd cDNAs from individual samples by thermodynamic methods, TGGE and cDNA heteroduplex analysis. We found that at least 70% of grapevine samples from locations close to hop gardens inNorthern Bohemia(Žatec and Úštěk hop production areas) were infected with HSVd forming populations containing quasispecies. Particular sequence variants, dominant in grapevines from wine-growing areas like Znojmo, were also found in minor private vineyards. HSVd was experimentally transmissible (80% success) from these samples to Osvald’s clone 72 of Czech hop, where according to the cDNA library screening, one of the dominant HSVdg variants corresponding to AC E01844 was detected in early populations three weeks p.i. HSVd was detected neither in reproduction materials nor in examined hop gardens. However a potential danger for hop cultivation, consisting in the high biological potential of HSVd spread is discussed.