Abstract does not appear. First page follows.

History of the Disease

Leafroll of grapevine has been recognized as a disease for more than a century, but the first indication of its viral nature was given by (Scheu (1936))2 when the disease was shown to be seed and graft transmitted. In California, (Harmon and Snyder (1946)) described a disease with symptoms of leafrolling that produced white berries in normally red-fruited grapevines of the variety Emperor. They accomplished graft transmission of the “white Emperor” disease to healthy grapevines. White Emperor was later proved identical to leafroll diseases of Germany and France, all of which were recognized as viral in origin (Goheen, et al., 1958); (Yuittenez, 1958).

Early descriptions of the disease

Leafroll is known by several names in the French literature; early stages are referred to as “rougeau or flavescence” (Vidal, 1943) and later stages are termed “brunissure” (Cook and Goheen, 1961).

Rougeau (or red plague) was a term applied by early French viticulturists to a disease of the leaves described as occurring “in the summer owing to hot south winds after a fog.” This description of the disease was included in Thiebaut de Berneaud’s book, The Vine dresser’s Theoretical and Practical Manual, translated from the second edition by Felix Pascalis, M.D., in 1829. The appearance of rougeau was described as sudden, with a reddening of the leaves which fell within 2 days; fruits became wrinkled and dry. It is problematical whether this condition would be called leafroll today. Reddening of the leaves is a valid symptom but the disease generally progresses much more slowly.

The next description of leafroll is attributed to Fabre, 1853, who observed that the leaves turned remarkably red and slowly became wholly or partially desiccated. Fabre recognized that the disease appeared each year and was transmitted from one vine to another, but he associated no specific parasite with transmission of the disease and concluded that its nature was a mystery (Ravaz and Verge, 1924). (Louis Leclerc (1853)) stated:

“I have seen this Rouge or Rouget in Languedoc, where it has been little known until now; it is acknowledged to have contributed a large part to the disaster of this year. Rouge has been observed more frequently in Bourgogne. People completely ignore this malady which attacks the leaf with a beautiful red color and paralyzes its functions.”