downy mildew

noun

1

: any of various parasitic lower fungi (family Peronosporaceae) that produce whitish masses of sporangiophores or conidiophores on the undersurface of the leaves of the host

2

: a plant disease caused by a downy mildew

Examples of downy mildew in a Sentence

Recent Examples on the Web

Late-summer diseases include powdery and downy mildew, blight, leaf spot, and root rot. —Mary Marlowe Leverette, Southern Living, 15 Aug. 2025

Suzanne mentioned two products that are preventive biological disease controls of powdery mildew, blackspot, botrytis, rust and downy mildew. —Rita Perwich, San Diego Union-Tribune, 5 July 2025

Gardeners will be glad to know plants are resistant to impatiens downy mildew. —Dawn Pettinelli, Hartford Courant, 12 Jan. 2024

Minor diseases like powdery mildew or nuisance pests like aphids are less of a concern, but more substantial diseases like downy mildew and pests like allium leaf miner are best managed with prevention. —Miri Talabac, Baltimore Sun, 7 Sep. 2023

Word History

First Known Use

1886, in the meaning defined at sense 1

Rhymes for downy mildew

• hullabaloo
• accrue
• ado
• ainu
• aircrew
• airscrew
• anew
• askew
• baboo
• babu
• bamboo
• beaucoup