Symptoms
Early symptoms are small red lesions on succulent
stems. The lesions become swollen and broadly conical in
about 6 months. On susceptible cultivars, large, swollen
cankers develop, with deep cracks and numerous fruiting
bodies, after 2 to 3 years. Stems may be girdled and killed.
Disease
cycle
The fungus overwinters in infected canes.
Current-season stems are infected by ascospores or conidia
in late spring. The optimum temperature for growth and sporulation
of the fungus is 77 to 82ºF (25 to 28ºC). Eight
races of the fungus are known. |
