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Phomopsis
cane and leaf spot - Phomopsis viticola
Annemiek
Schilder, MSU Plant Pathology |
| Home > Scouting guide> phomopsis cane and leaf spot |
| Phomopsis cane and
leaf spot occurs in most grape-growing regions.
Infected leaves have small, yellowish spots with dark brown centers and may
be puckered. On petioles, shoots and rachises, elongated black spots or
streaks develop that make the tissue brittle. Most shoot lesions occur
on the basal three to six internodes.Young tissues are most susceptible. Symptoms appear 21 to 30 days after infection. Rachis and berry infections become
apparent later in the season. Infected rachises wither, causing berries
or entire clusters to drop prematurely. Berries turn brown and shrivel. Prolonged rainy, cold weather in spring and early summer promotes the disease. The optimum temperature for infection is between 59 and 68ºF (15 to 20ºC). The fungus overwinters in bark of infected canes. |
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| Fruiting bodies appear as black specks on berry skin. |
Lesions on rachis and shoot. |
Infection through berry skin. |
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