Researchers have been working on a project to get a better understanding of a viticulture issue now known as Sudden Vine Collapse (SVC). Initially discovered in the Lodi area, the issue can cause mature vines that have growing canopies to collapse and die within a relatively short period of time. The preliminary research is beginning to shed some light on the possible cause for SVC.
“This problem used to be called mystery vine collapse because we didn’t know what was the cause. The symptoms were suddenly some of the vines were dying in the middle of the vineyard and we had no idea at that time,” said Akif Eskalen, Extension Specialist and Plant Pathologist at UC Davis. “Now we have an idea of what we are dealing with, so the name changed to Sudden Vine Collapse instead.”
A task force has been working to address the issue of SVC as the problem has been detected in the Central Valley and areas of the Central Coast. Working with plant samples from different regions of California the research team has been able to narrow down potential causes. “We found out that all the grapevines that are showing the sudden vine collapse have a combination of infection of more than one virus disease, including grapevine leafroll tree viruses and vitiviruses. We have also seen the association of the common grapevine trunk diseases which are fungal pathogens,” Eskalen explained.
While the COVID-19 pandemic has slowed some of the progress in the ongoing research project, Eskalen noted that the work will be ongoing. Another common denominator in the preliminary findings is that some of the more virus sensitive rootstocks also appear to be more susceptible to being affected by SVC. Because mealybug is a common vector for multiple grapevine viruses, monitoring and management of the invasive pest is a critical component of preventing SVC in vineyards.
“For the farmers it is very, very important to have effective mealybug control in their vineyard,” said Eskalen. “If you see a mealybug in your vineyard, if you are unable to control it, if the grapevine is on the Freedom rootstock, you could see this kind of Sudden Vine Collapse in your vineyard.”