Valsa malicola. [Descriptions of Fungi and Bacteria].
A description is provided for Valsa malicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Valsa malicola is associated with dieback of Malus twigs, especially weakened by other factors, for example when frozen, burnt, wounded, injured by insects or attacked by other pathogens. HOSTS: On dead or dying twigs of Malus species, and other Maloideae (Cotoneaster, Crataegus, Cydonia, Pyracantha, Pyrus, Rosa). The fungus can also be found on other members of the Rosaceae (e.g. Prunus), but only infrequently, and mainly as the anamorph. GEOGRAPHICAL DISTRIBUTION: Asia: Armenia, Azerbaijan, China, Republic of Georgia, Kazakhstan, Russia. Europe: Austria, Czech Republic, Germany, Italy, Latvia, Lithuania, Portugal, Rumania, Russia, Slovakia, Sweden, Switzerland, UK, Ukraine. North America. TRANSMISSION: Both conidia and ascospores are air-borne, especially under humid conditions. Brightly coloured droplets or tendrils of conidia are often exuded from conidiomata after rain.