scurf
Scurf is a descriptive term for a crusty, scaly layer on the surface of a material or organism. In everyday language, it most often refers to dandruff—the flaky sheddings of the scalp that can accompany itching. The word derives from Old English scurf meaning crust or scale.
In human dermatology, scurf or dandruff is common and usually results from the turnover of scalp skin
In agriculture, scurf describes superficial crusts or patches on tubers like potatoes or on seeds and bulbs.
Language notes: The term is used across disciplines to describe superficial crusts; it is not a disease