Enology UC Davis June 1990 1. The choice of planting stock will have an enormous impact on the health and quality of the planting for the life of the vineyard. If virus-infected planting stock is used, no subsequent cultivation practices or treatments will improve the diseased condition, short of replacing the vines.
Grapevines carrying virus disease are a liability to the grower for many reasons.
Fanleaf-infected vines can also serve as a source of infection if Xiphinema index dagger nematodes are present in the soil to transmit the virus to healthy vines. These nematodes can survive up to 10 years on roots left behind after a vineyard is removed and will infect healthy vines that are planted later in the same site. Virus disease should therefore be avoided for the betterment of current and future vineyards. It is also important to choose planting stock that is true to variety. If the vines are found to be incorrectly identified, they may be unsuitable for the product for which they were planted.