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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #403274

Research Project: Disease Management and Improved Detection Systems for Control of Pathogens of Vegetables and Strawberries

Location: Crop Improvement and Protection Research

Title: Seed transmission of spinach downy mildew, and analyses of airborne lettuce and spinach downy mildew

item Klosterman, Steven

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/14/2023
Publication Date: 3/14/2023
Citation: Klosterman, S.J. 2023. Seed transmission of spinach downy mildew, and analyses of airborne lettuce and spinach downy mildew. California Leafy Greens Research Program Annual Meeting, March 14, 2023, Pismo Beach, California.

Interpretive Summary:

Technical Abstract: Downy mildew diseases of lettuce and spinach, caused by Bremia lactucae and Peronospora effusa, respectively, are constraints on the production of these crops. In plant isolator experiments conducted in the winters of 2021 and 2022, we confirmed that downy mildew disease was transmitted from seed infested with the oospores of P. effusa. Additionally, spinach downy mildew was transmitted from oospore-infested leaf debri that had been incorporated into the soil of the isolators. Ongoing work quantifying the airborne spores of both P. effusa and B. lactucae in the Imperial, Coachella, and Salinas Valleys of California revealed increases in spore amounts were correlated with crop acreage planted, but there was a period in October lasting for weeks in the Imperial Valley where spores were not detected. These results emphasize the need to develop practical solutions to limit the introduction of downy mildew on spinach seed, and also provide information that can be useful for downy mildew forecasting for lettuce and spinach.