Photos of Grapevine Red Blotch (IMAGE) University of California - Davis Caption Grapevine red blotch disease, as shown the leaf above on the right, can have a significant impact on wine quality. Credit Raul Girardello/UC Davis Usage Restrictions Please credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.