| characterization of a plasmopara species on ambrosia artemisiifolia, and notes on p. halstedii, based on morphology and multiple gene phylogenies. | common ragweed (ambrosia artemisiifolia) is an invasive and highly allergenic plant species, on which two species, plasmopara halstedii and plasmopara angustiterminalis, have been recognized to cause downy mildew disease. in this study, morphological and molecular patterns of seven plasmopara specimens collected from a. artemisiifolia in canada, hungary, and usa were compared with those of p. halstedii and p. angustiterminalis from helianthus and xanthium, respectively. analyses of partial seque ... | 2009 | 19619650 |