Powdery scab, is a disease of potato tubers. It is caused by the cercozoan Spongospora subterranea f. sp. subterranea and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the disease, progressing to raised pustules containing a powdery mass. Powdery scab has a cosmetic effect on tubers, which can result in rejection of potatoes. The powdery pustules contain resting spores, which release anisokont zoospores which can infect the root hairs of potatoes or tomatoes.
Crop rotation system can help avoid the problem of powdery scab. Potatoes which have been infected can be peeled to remove the infected skin and the remaining inside of the potato can be cooked and eaten.
Famous quotes containing the word scab:
“Goodbye, boys; I’m under arrest. I may have to go to jail. I may not see you for a long time. Keep up the fight! Don’t surrender! Pay no attention to the injunction machine at Parkersburg. The Federal judge is a scab anyhow. While you starve he plays golf. While you serve humanity, he serves injunctions for the money powers.”
—Mother Jones (1830–1930)