Plasmopara halstedii reported for the first time from Germany
Plasmopara halstedii (EU Annex II/A2) has been reported for the first time in Germany from commercial fields of sunflower (Helianthus annuus). The pathogen was first observed at Tübingen (Württemberg) in 1986 on a small non-commercial plot, which was formerly used to grow garden ornamental plants. Since no sunflower field was in the vicinity of approximately 10 km at that time, it is most likely that the pathogen was introduced by oospore-containing seeds, possibly by birdfood. Later, P. halstedii was observed for the first time in agricultural sunflower fields near Rastatt, Baden, in 1992. So far, 8 races of P. halstedii have been described in North America. In Tübingen, races 1 and 4 were identified by using a set of differential sunflower lines. In commercial fields near Baden, plants were found infested by race 5 which is found for the first time outside North America. The authors pointed out that most of the cultivars grown in Germany, though resistant to race 1, are not resistant to races 4 and 5. According to the EPPO Secretariat this is the first report of P. halstedii in Germany.
Spring, O.; Miltner, F.; Gulya, T.J. (1994) New races of sunflower downy mildew (Plasmopara halstedii) in Germany.
Journal of Phytopathology, 142 (3-4), 241-244.