The long‐term effect of Stolbur phytoplasma on grapevines in the Golan Heights

Background and Aims Grapevine yellows caused by different phytoplasma strains share common epidemiological and horticultural characteristics. The aim of this study was to determine the implications of the disease epidemiology for growers. Methods and Results Cabernet Sauvignon and Chardonnay blocks were mapped annually for disease symptoms, and new infections and vine recovery were assessed. We measured yield and pruning weight of healthy, symptomatic and recovered vines, as well as the presence of phytoplasma particles in leaves, shoots and roots. We show a high remission rate in Cabernet Sauvignon vines infected with Stolbur phytoplasma and a low rate in Chardonnay. One year after symptom remission, vines of both cultivars had yields significantly higher than that of symptomatic ones, and after two years the yield of Cabernet Sauvignon vines did not differ from that of healthy vines. Vine vigour remained low for at least two years. Phytoplasma particles were found in all the symptomatic vines, in only one of 12 recovered vines, and were absent in healthy vines. Conclusions A high rate of recovery from phytoplasma was recorded in Cabernet Sauvignon and a lower rate in Chardonnay, coupled with good yield performance in recovered vines. Significance of the Study We do not recommend uprooting diseased vines as most vines recover from the disease and return to normal production.