Evaluation of Oxathiapiprolin for the Management of Sunflower Downy Mildew.

Downy mildew is a yield-limiting disease of sunflower, caused by the pathogen . Zoospore infection of root tissue shortly after planting results in systemic infection, causing postemergence damping off or severe stunting and head sterility. Although fungicide-applied seed treatments can be an effective management tool, the pathogen is resistant to phenylamide fungicides in many growing regions, and other available fungicides have limited efficacy.

Phenotypic Diversity of Puccinia helianthi (Sunflower Rust) in the United States from 2011 and 2012.

Puccinia helianthi, causal agent of sunflower rust, is a macrocyclic and autoecious pathogen. Widespread sexual reproduction of P. helianthi was documented in North Dakota and Nebraska for the first time in 2008 and has since frequently occurred.