Skip to main content
ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #382967

Research Project: Management of Pathogens for Strawberry and Vegetable Production Systems

Location: Crop Improvement and Protection Research

Title: Epidemiology of spinach and lettuce downy mildew

item Klosterman, Steven

Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 3/31/2021
Publication Date: 3/31/2021
Citation: Klosterman, S.J. 2021. Epidemiology of spinach and lettuce downy mildew. California Leafy Greens Research Program Annual Meeting, March 31, 2021 (virtual).

Interpretive Summary:

Technical Abstract: Spinach and lettuce downy mildew diseases are caused by the obligate oomycete pathogens Peronospora effusa and Bremia lactucae, respectively. In conventional spinach and lettuce production, downy mildew is effectively controlled using fungicides, but control options in organic production are limited since fungicides are not available for use in organic production. The development of disease resistant cultivars is key for disease control in organic spinach and lettuce production. However, P. effusa and B. lactucae often overcome resistance in the field as new races of the pathogen can occur with different pathogenic capabilities. Since P. effusa produces both long-lived oospores and sporangia, tracking primary inoculum sources in seed can be useful to limit the introduction of the pathogen into growing regions, and studies are underway that examine the rate of seed transmission and survival of oospores and sporangia of this pathogen. Additional experiments are underway for examination of airborne inoculum loads of both lettuce and spinach downy mildew . Increasing our understanding of spinach and lettuce downy mildew epidemiology is essential to develop new approaches for integrated disease management.