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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #379352

Research Project: Breeding, Genomics, and Integrated Pest Management to Enhance Sustainability of U.S. Hop Production and Competitiveness in Global Markets

Location: Forage Seed and Cereal Research Unit

Title: The hop downy mildew pathogen Pseudoperonospora humuli

item PURAYANNUR, SAVITHRI - North Carolina State University
item Gent, David - Dave
item MILES, TIMOTHY - Michigan State University
item RADISEK, SEBASTJAN - Slovenian Institute Of Hop Research And Brewing
item QUESADA-OCAMPO, LINA - North Carolina State University

Submitted to: Molecular Plant Pathology
Publication Type: Review Article
Publication Acceptance Date: 3/14/2021
Publication Date: 5/4/2021
Citation: Purayannur, S., Gent, D.H., Miles, T.D., Radisek, S., Quesada-Ocampo, L. 2021. The hop downy mildew pathogen Pseudoperonospora humuli. Molecular Plant Pathology. 22(7):755-768.

Interpretive Summary: This review article introduces and summarizes knowledge of Pseudoperonospora humuli, the causal agent of the disease hop downy mildew. We review signs and symptoms of the disease, crop damage, disease biology and ecology, and current management practices. We also review recent advancements in genomic research that has discovered a suite of pathogen-produced molecules important in disease development and the potential for plant breeding efforts to be informed and accelerated through these advancements.

Technical Abstract: Pseudoperonospora humuli (Miyabe & Takah.) G.W. Wilson, (1914) is an obligate biotrophic oomycete that causes downy mildew, one of the most devastating diseases of cultivated hop, Humulus lupulus L. Downy mildew occurs in all production areas of the crop in the Northern Hemisphere and Argentina. The pathogen overwinters in hop crowns and roots, and causes considerable crop loss. Downy mildew is managed by sanitation practices, planting of resistant cultivars, and fungicide applications. However, the scarcity of sources of host resistance, and fungicide resistance in pathogen populations complicates disease management. This review summarizes the current knowledge on the symptoms of the disease, life cycle, virulence factors, and management of hop downy mildew, including various forecasting systems available in the world. Additionally, recent developments in genomics and effector discovery, and the future prospects of using such resources in successful disease management are also discussed.