The Distribution of Grapevine Yellows Disease Associated with the Buckland Valley Grapevine Yellows Phytoplasma

Three blocks of Chardonnayin one vineyard in the Buckland Valleyof Victoria, Australia, were surveyed over 4 years for grapevine yellows disease (GYd). Buckland Valley grapevine yellows phytoplasma (BVGYp) was the only phytoplasma detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis in GYd affected grapevines. GYd affected manygrapevi nes and was characterized byremi ssion of disease, some recurrence and occurrences in previouslyuna ffected grapevines. A regional surveyof the Buckland Valleyindica ted that both GYd and BVGYp occurred in the same restricted grape growing area. Within this area, BVGYp was detected in two vineyards that had been established using planting material from different sources. One could therefore speculate that BVGYp was present in these grapevines as a result of aerial transmission and was not present in the original planting material