Mycologia, DEUTEROMYCOTINA, HYPHOMYCETALES, DEMATIACEAE .
Identification, Description, Biology, Epidemiology, Treatement, Possible misleading, Images
The disease affects the leaves, the twigs and the fruits.
In spring, red dots (ab. 1 mm diameter) occur all over the leaves, then expand into larger circular lesions (ab. 3 mm diameter) with a necrotic brownish center and purple red margins. The central necrotic area gradually gives way and drops out resulting in a hole.
The twig lesions have clear-cut brown margins and a necrotic center which does not drop.
Early autumn lignification of infected twigs is hindered and the lesions will grow into cankers.
The fruits are covered by large quantities of spots sometimes rough and corky and covered by a gummy exudate.
Even if they reach an adult stage the fruits are severely damaged.
The fungus may persist several years in the cankers and the buds of infected twigs. If the conditions are favourable it may even continue to grow during the winter.
In spring, the conidia generated by this inoculum source are carried by the rain and infect the flowers and the young leaves.
In dry conditions the conidia are viable several months but cannot be detached and spread by the wind.
Rains are necessary for their dispersal. In humid conditions they can germinate at highly varying temperatures above 2 ░C., which accounts for the winter infection of buds.
Remove the cankered twigs before and after winter.
Avoid water-spraying in the fields.
Use the fungicidal treatments recommended in your area, applied as for Taphrina deformans .
Other factors causing leaf-hole (fungi or bacteria).
HYP3 on line : Species (scientific name), Diseases (common names), Glossary, Crops.