Grapevine Viruses Found in Michigan to Support Healthy Vineyards

By Andi Anderson

Michigan’s wine grape industry plays a key role in the state’s economy, with an annual impact of over $6.3 billion. However, grapevines are often infected with plant viruses that can reduce yield and vine health.

To address this, Michigan State University (MSU) researchers are studying which grapevine viruses are affecting local vineyards.

Led by MSU’s Small Fruit and Hop Pathology program in partnership with the University of California, Davis, the research screened vineyards across Michigan using RT-PCR testing—similar to technology used for COVID-19 detection.

The goal was to identify common grapevine viruses in the state and raise awareness about the importance of diagnostic testing and clean planting practices.

Among the viruses detected, the Grapevine Rupestris Stem Pitting-Associated Virus (GRSPaV) was the most common. This virus can cause delayed bud break, reduced growth, lower yields, and overall decline in vine health.

Many vineyards across different regions of Michigan—northwest, southwest, middle, and southeast—showed signs of this and other viruses.

One reason for the spread is the diversity in grape types grown in the state, ranging from wine grapes to juice grapes, each with different virus susceptibility.

Another issue is that many growers use planting material from various locations across the country, which increases the risk of bringing in infected vines.

MSU’s Plant and Pest Diagnostics lab now offers virus testing services for growers, making it easier to detect and manage infections early. This study helps Michigan grape growers make informed decisions that will improve vineyard health and sustainability.

As Jenelle Jagmin of the Michigan Craft Beverage Council said, “This research provides valuable tools for growers to manage vineyard disease and support the long-term success of Michigan’s wine industry.”

With better awareness, testing, and use of virus-free plants, Michigan’s grape and wine industry can continue to thrive despite the challenges posed by vineyard viruses.

Photo Credit: michigan-state-university-msu