Phomopsis
canker and twig blight
Phomopsis
vaccinii (fungus)
Annemiek Schilder,
MSU Plant Pathology
Bill
Cline, NCSU Plant
Pathology |
| Phomopsis canker and twig blight occurs
in most blueberry-growing regions. |
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Symptoms
A typical symptom is sudden wilting and death
(flagging) of canes during the growing season. A sunken or
flattened area (canker) is often present at the base of the
cane. Reddish brown, spreading lesions develop on green stems
and twigs, which are eventually killed. Twig lesions often
originate from infected buds. Leaf spots may appear later
in the season. |
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| Flagging of canes (left); canker (right). |
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Disease cycle
The fungus overwinters in infected canes and
twigs. In the spring, spores are dispersed from fruiting bodies
by rain. The fungus is active from bud swell until after harvest.
Plants that have been wounded mechanically or damaged by freezing
are more susceptible to infection than undamaged plants. |
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| Young lesions (left) are brown and become bleached (middle) as they age. Fruiting bodies (right) develop in the bleached areas. |
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Above, spores ooze out of fruiting bodies. |
Management
Prune out infected canes; avoid wounding the
canes; plant resistant cultivars; limit overhead irrigation;
apply effective fungicides. |
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| Leaf spots forming (left). A lesion spreading from an infected bud in the spring (right). |
Fruit infection leads to white mold growth and soft fruit which split when squeezed. |
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