The Effects of Viruses and Viral Diseases on Grape and Wine

The grapevine is the plant species most susceptible to virus infections,. Virus effects on grapevine performances are generally accepted as potentially severe, although an exact estimation is difficult because of the complexity of factors influencing vine response. No doubts that diseases like infectious degenerations caused by nepoviruses are highly detrimental, impacting dramatically plant vigor and yield. More controversial is the effect due to ampeloviruses, closteroviruses and vitiviruses, the agents of leafroll and rugose wood. Grapevine is also infected by virus diseases considered 'minor' and whose impact is still unclear (fleck, vein mosaic, rupestris stem pitting, etc.). Nevertheless their presence should not be overlooked because possible synergistic negative effects with other major viruses cannot be excluded. Viruses are dangerous and elusive pathogens whose presence in vines must be prevented selecting and using clean propagation material.