powdery scab

noun

: a disease of potato tubers caused by a fungus (Spongospora subterranea) and characterized by nodular discolored lesions which at maturity burst to expose a powdery mass of spores in circular pits surrounded by the lighter colored frayed remnants of the skin of the tuber

called also pock scab

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now