First four sentences of introduction: California vineyards are being planted with increasingly diverse rootstock and scion materials. A large part of the scion wood is uncertified and, therefore, more likely to be virus infected. Sick, dead, or dying grapevines were observed in young vineyards throughout the state. Symptoms, vineyard case histories, and our field trials strongly suggest that in many cases, young vine decline can be caused by grapevine latent viruses (Martelli, 1993).
