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Leafroll virus

Symptoms are most obvious in fall. Infected vines are slightly smaller than healthy vines. Leaves become yellow or reddish purple as the season progresses; the main veins remain green. By late summer, the leaves start rolling downward, beginning at the base of the shoot. At harvest, fruit clusters are small, poorly colored and low in sugar. The disease does not kill the vine but will remain chronic. Not all infected vines show symptoms. The leafroll virus spreads primarily via infected nursery stock and the grape mealybug. Within-field spread by mealybug is very slow.


This disease is found in most grape-growing areas.

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The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.