First Paragraph: Leafroll, a virus-like disease of grapevines, is worldwide in distribution. In some viticultural regions, nearly 100% of vines are infected. Despite having been recognized for nearly 150 years, leafroll continues to be a serious problem in all major grape growing areas. Clean stock programs have been established in several countries in order to produce, maintain, and distribute grapevines which are free of leafroll and other diseases.
