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Life history of a Puccinia coronata form infecting two invasive wetland plants
Nicholas Greatens - Department of Plant Pathology, University of Minnesota. Les Szabo- USDA-ARS Cereal Disease Laboratory, Yue Jin- USDA-ARS Cereal Disease Laboratory, Klara Peterson- Department of Plant Pathology, University of Minnesota, Melissa Lim- USDA ARS

In 2017, heavy rust infections on Frangula alnus(glossy buckthorn) were observed in the metro area of the Twin Cities (MN). Infections were observed on leaves, leaf petioles and axillary buds that led to a reduction of growth on new shoots, flowers and fruits. Phalaris arundinacea (reed canary grass) adjacent to infected F. alnus developed uredinia following the release of aeciospores from F. alnus. Experiments were conducted to determine the rust pathogen’s life cycle and host specificity by inoculating P. arundinacea, as well as other grasses and cereal crops with aeciospores collected from F. alnus. Results from preliminary studies indicated that this rust fungus is heteroecious, completing its life cycle by alternating between R. frangula and P. arundinacea, and that the fungus does not infect oats, barley, wheat, rye, or a number of other grasses except Phalaris and Calamagrostis spp. Microscopic examination of spore morphologies indicated that this rust fungus belongs to the Puccinia coronata complex. Experiments are in progress to determine telial and aecial host specificities and phylogenetic relations with other known forms of P. coronata.