Common scab and powdery scab: Differences, symptoms and management

While powdery scab doesn’t develop in a potato crop until tuberization, management of the disease and exclusion of inoculum starts at time of planting. Powdery scab shares part of its name and some similarity in symptomology with common scab, but the two diseases are unique in nature and management. Both diseases can significantly reduce tuber appearance and quality. The table in this article on these diseases summarizes differences between the two “scabs” and was included in a UWEX fact sheet by Delahaut and Stevenson from 2009. (This article by Amanda J. Gevens, Associate Professor & Extension Vegetable Plant Pathologist, UWMadison, Dept. of Plant Pathology, with contributions from Professor Emeritus Walt Stevenson. Full article)