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Leafroll - Leafroll virus
Annemiek
Schilder, MSU Plant Pathology |
| Home > Scouting guide> leafroll |
| Leafroll
virus is found in most grape-growing areas. 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 is spread primarily
via infected nursery stock and the grape mealybug. Within-field spread by
mealybug is very slow. |
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| Photos: Tom Zabadal |
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Left, infected
Chardonnay leaf beside a healthy leaf.
Photo: Tom Zabadal |
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