Grapevine Virus Resources

CGCN Resources

Browse these resources to learn about grapevine viruses.

Red Blotch | CGCN

Grapevine Red Blotch Disease
Grapevine Red Blotch Virus (GRBV)

Grapevine red blotch disease is caused by Grapevine Red Blotch Virus (GRBV).  GRBV is known to infect all major wine grape varieties as well hybrids and table grapes. GRBV is known to present in all the grape growing regions of North America as well as a few other grape growing regions around the world. 

Visual Symptoms and Impact 

  • Red or purple blotches on leaves on mature leaves in red-fruited cultivars
  • Yellowing or mild necrosis on the mature leaves in white-fruited cultivars
  • Symptoms can be confused with Leafroll disease or potassium/magnesium deficiency
  • Symptoms on hybrid cultivars are less apparent or show no clear symptoms
  • Typically, symptoms start to appear after the véraison
  • Uneven ripening of berries and thin clusters can be seen due to GRBV infection
  • GRBV infection decreases the vine productivity and the life span of the vineyard
  • Reduced yield and poor quality of grapes would result in significant economic losses
  • Negatively impacts the sugar content in the fruit at maturity  

Spread

  • Primary spread is by propagating the GRBV infected planting material
  • Threecornered alfalfa hopper, Spissistilus festinus (Say) is a reported vector of GRBV in California and other possible insect vectors are suspected, and the research on identifying potential insect species is under progress in Canada

Control and Management Options

  • Once the vine is infected, there is no cure for grapevine red blotch disease. Prevention is the best strategy to manage the spread
  • Use of virus-free certified planting material is highly recommended
  • Make sure both rootstock and scion wood material is tested for the virus  
  • Roguing or removal of infected material is a good practice to reduce the incidence and spread of red blotch disease

Leaf Roll | CGCN

Grapevine Leafroll Disease
Grapevine leafroll-associated viruses (GLRaV)

There are more than five different virus species that cause Grapevine leafroll disease (GLD) are known as “Grapevine leafroll-associated viruses (GLRaVs)”. The different species of GLRaVs are referred as GLRaV-1, -2, -3, -4 and -7. They are many variants of GLRaV-2, -3 and -4 are known to present that are associated with GLD.   GLRaV-3 is the most common among the different species of GLRaVs and known to be present in all grape growing regions of Canada.

Visual Symptoms

  • Red or purple coloration on mature leaves with green veins in red-fruited cultivars
  • Yellowing on the mature leaves in white-fruited cultivars
  • Backward rolling of mature leaf margins commonly found in both white and red fruited cultivars
  • Symptoms can be confused with grapevine red blotch disease or potassium/magnesium deficiency
  • Symptoms are clearer on red-fruited wine grape cultivars
  • Symptoms on hybrid cultivars are less apparent or show no clear symptoms
  • Typically, symptoms start to appear after the véraison
  • Uneven ripening of berries and thin clusters can be seen due to GLRaVs infection
  • GLRaVs decreases the vine productivity and the life span of the vineyard
  • Reduced yield and poor quality of grapes would result in significant economic losses 

Spread

  • Primary spread is by propagating the GLRaVs infected planting material
  • Some species of Mealybug and soft scale insects are known spread GLRaVs except for GLRaV-2
  • There is no known insect vector reported for GLRaV-2
  • Grape mealybug and European fruit lecanium scales are two known species reported to be present in Canada.

Control and Management Options

  • Once the vine is infected, there is no cure for grapevine leafroll disease. Prevention is the best strategy to manage the spread
  • Use of planting material from certified sources that is produced from virus-tested rootstock and scion material is highly recommended
  • Controlling mealybugs and soft scale insect populations will also reduce the spread of GLD
  • Roguing or removal of infected material is a good practice to reduce the incidence and spread of GLD

Pinot Gris Virus | CGCN

Grapevine Pinot Gris Virus
Grapevine Pinot Gris Virus (GPGV)

Grapevine Pinot gris Virus (GPGV) is proposed as a provisional new species belonging to the genus Trichovirus in the family Betaflexiviridae. 

Visual Symptoms

  • Chlorotic mottling and leaf deformation and reduced growth of infected vines are the common symptoms if infected with a symptomatic strain of GPGV.
  • Symptoms are similar on both white and red fruited cultivars.
  • Symptoms can be seen from early spring on leaves
  • The asymptomatic stain of GPGV can be present but shows no symptoms

Control and Management Options 

  • Prevention is the best strategy to prevent the spread
  • Use of planting material from certified sources that is produced from virus-tested rootstock and scion material is highly recommended
  • Roguing or removal of infected material is a good practice to reduce the incidence and spread of Grapevine Pinot gris virus 

Information courtesy of:
Sudarsana Poojari
Senior Scientist, Cool Climate Oenology and Viticulture Institute
Adjunct Professor, Department of Biological Sciences
Brock University |1812 Sir Isaac Brock Way | St. Catharines, ON  L2S 3A1

From Our Team

  • The CGCN is trying to mitigate the virus issue at an early stage through a national organization. Our goal is healthy vineyards, and a competitive wine industry in Canada.
    CGCN-RCCV
Questions? Feel free to contact us.

Learn more about CGCN, or apply to our certification program.

Contact Us