In research done by Wendy McFadden-Smith (OMAFRA), Sudarsana Poojari and Jean-Philippe Parent (AAFC) it was discovered that symptoms of Grapevine Leafroll Disease are more apparent on red-fruited vines than whites, although this does depends on many environmental factors including age of the vine, and stage of the virus infection.
Typical symptoms of Leafroll disease in red cultivars include red-purple discoloration, and rolling backwards of the leaves. In white varietals, this is not as prevalent, although can sometimes be seen closer to the end of the growing season.
Although Grapevine leafroll and Grapevine red blotch can be similar in appearance, there are slight differences observed such as no downward rolling of leaf margins in red blotch infected red and white cultivars.
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