Abstract
Transmission experiments indicate that the disorder known as red leaf in California and variously as rougeau, flavescence, or brunissure in France is probably grape leafroll.
Leafroll causes affected vines to develop more slowly than healthy vines. It causes fruit sugar at harvest to be generally lower than that from healthy vines. This difference is not apparent in early summer. In unirrigated vineyards yields are about one third of those of healthy vines. Wood production is also reduced, and fruit clusters are fewer and smaller.
- Copyright 1959 by the American Society for Enology and Viticulture