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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #349576

Title: Downy Mildew

item ZHU, ZHENDONG - Chinese Academy Of Agricultural Sciences
item Chen, Weidong

Submitted to: North Dakota State University Extension Service
Publication Type: Book / Chapter
Publication Acceptance Date: 2/26/2018
Publication Date: 3/15/2018
Citation: Zhu, Z., Chen, W. 2018. Downy Mildew. North Dakota State University Extension Service. Online:

Interpretive Summary: The fungus-like organism Peronospora viciae f. sp. pisi causes downy mildew of peas. In this chapter of the pea diseases diagnostic guide, we point out the symptoms of the disease with pictures, factors affecting the disease, and important facts to help growers diagnose and manage downy mildew of peas.

Technical Abstract: Downy mildew causes serious damage to peas throughout the world. The disease is caused by the Oomycete Peronospora viciae f. sp. pisi. Infections can be systemic or local. Systemic infection causes stunted and distorted plants. Local infections cause lesions that appear as greenish yellow to brown colored angular blotches on upper leaf surfaces. The pathogen forms oospores that can survive for 10 to 15 years. The pathogen can be carried on seeds, may survive in soil and also be disseminated by wind. Management tools for downy mildew include planting resistant cultivars, rotating crops and appling fungicides.