Also called false mildew. any fungus of the family Peronosporaceae, causing many plant diseases and producing a white, downy mass of conidiophores, usually on the under surface of the leaves of the host plant.
Plant Pathology. a disease of plants, characterized by mildewed, distorted, and yellowed foliage, caused by any of several fungi of the family Peronosporaceae, as of the genera Peronospora and Phytophthora.
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How to use downy mildew in a sentence
downy mildew spreads and does most damage in hot wet weather.The Grapes of New York | U. P. Hedrick
Spraying with bordeaux mixture as indicated for black-rot will keep downy mildew in check.The Grapes of New York | U. P. Hedrick
Practice clean cultivation from the very beginning in order to help control black rot and downy mildew.
The berries, however, do not become soft and shrunken as when attacked by the downy-mildew.Manual of American Grape-Growing | U. P. Hedrick
The two leaf troubles are respectively known as blight or downy mildew and the Macrosporium disease.Farm Gardening with Hints on Cheap Manuring | Anonymous
British Dictionary definitions for downy mildew
a serious plant disease, characterized by yellowish patches on the undersurface of the leaves, caused by the parasitic fungi of the family Peronosporaceae, such as Peronospora destructor: affects onions, cauliflower, lettuce, etc
any of the fungi causing this disease
- Compare powdery mildew
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for downy mildew
A disease of plants caused by oomycete organisms of the order Peronosporales and characterized by gray, velvety patches of spores on the lower surfaces of leaves. Downy mildew of the grapevine nearly destroyed the French wine industry in the 1870s, spurring the development of the first chemical pesticides used on plants.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.