Grafting in perennial fruit crops has been practiced since ancient times, originating with the Chinese and Greeks. In modern-day cropping systems, grafting is often used to enhance fruit tree and vine productivity, confer disease or pest resistance, and tolerate certain soil types. As a component of grafting, rootstocks were developed to improve fruit crop quality and survivability. Rootstocks consist of the lower portion of the tree or vine below the graft union that enhances plant tolerance and/or resistance to certain soil conditions or pests.
Most of the grapes in Washington State are grown on their own roots (non-grafted) due to the limited presence of phylloxera. This aphid-like insect forms galls on roots and occasionally leaves, and can cause premature shoot defoliation, vine decline, and eventual death. Since there are no chemicals to treat phylloxera, most growers simply graft wine grape varieties onto phylloxera-resistant rootstocks.