Definition

Noun: 1. A fungal plant disease: A common plant disease caused by fungi, primarily from the order Erysiphales. It is characterized by the appearance of a white or grayish, powdery fungal growth on the surfaces of leaves, stems, and sometimes flowers and fruits.

Usage

This term is used specifically in the context of plant pathology, gardening, agriculture, and botany to describe both the visible symptoms of the disease and the causal fungi themselves.

Examples

• Noun:
  • The rose bushes were severely affected by powdery mildew after the humid spell.
  • Gardeners often use a baking soda solution to control powdery mildew on squash plants.
  • Unlike downy mildew, powdery mildew fungi grow primarily on the surface of the plant.

Advanced Usage

• As a mass noun: The term is often used in a general, non-countable way to refer to the disease condition.
  • The vineyard manager is monitoring the grapes for signs of powdery mildew.
• Referring to the causal agent: In more technical contexts, it can refer specifically to the fungal pathogen.
  • The powdery mildew overwinters in plant debris.

Variants and Related Words

• Mildew (n): A broader term for various types of fungal growth on plants or organic materials. Powdery mildew is a specific type of mildew.
• Downy mildew (n): A different type of plant disease caused by water molds (oomycetes), which appears as fuzzy, often purplish-gray growth on the undersides of leaves.

Synonyms

• White mold (This is a less precise, general descriptive term sometimes used by gardeners.)
• Fungal leaf spot (This is a broader category; powdery mildew is a specific type of fungal affliction.)

Related Phrases/Idioms

There are no common idioms or phrasal verbs using "powdery mildew." It is a technical compound noun.

Noun

1. any of various fungi of the genus Erysiphe producing powdery conidia on the host surface