Authors: Huhtinen, Seppo & Alanko, Pentti & Mäkinen, Yrjö
Journal: Karstenia, Volume 41 (2001), Issue 1, pages 31-36.
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Key words: Microesphaera, Caragana, Finland, invasion history
Abstract: The invasion of Microsphaera palczewskii Jacz. an Asian-origin parasitic fungus ofCaragana Fabr. in Finland is reported. The first specimen was collected in South Finland in 1981 and now the species is distributed throughout the country to all areas where Caragana arborescens Lam. is cultivated. The epidemic spread caused a total decline of the occurrence of M. trifolii (Grev.) U. Braun on Caragana. The last record of M. trifolii dates back to year 1987. Mature cleistothecia of M. palczewskiican be found from mid-July onwards, conidial stage from the beginning of June. Specimens showing conidial stage only can be observed even in September and October, which indicates a continuous infection activity. Recent field observations do not support the reported overwintering in wooden parts. The source of infection is most probably fallen leaves with plenty of cleistothecia.