powdery mildew

noun

any of various parasitic fungi of the ascomycete order Erysiphales, which produce a powderlike film of mycelium on the surface of host plants.

Plant Pathology. a disease caused by powdery mildew, characterized by yellowing and death of the foliage and a white mealy growth of fungus on the surface of above-ground parts.

Origin of powdery mildew

An Americanism dating back to 1885–90

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for powdery mildew

powdery mildew

noun

a plant disease characterized by a superficial white powdery growth on stems and leaves, caused by parasitic ascomycetous fungi of the family Erysiphaceae: affects the rose, aster, apple, vine, oak, etc

any of the fungi causing this disease

Compare downy 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

Science definitions for powdery mildew

powdery mildew

[pou′də-rē]

Any of various important plant diseases caused by fungi, especially those of the family Erysiphaceae, which produce powdery conidia on the surface of the hosts leaves and stems.