Integrated approach necessary to control powdery scab

Summary

Powdery scab is a nasty seed-borne, soil-borne and even, through contaminated dust, air-borne potato disease. The culprit is Spongospora subterranea f. sp. subterranea (abbreviated as SSS), an obligate, parasitic plasmodiophorid with a wide host range. This parasite affects root systems, but also tubers. Moreover, it is the vector of the potato mop-top virus. From the Andes, it spread to most potato growing regions, especially in temperate zones. Its polycyclic life cycle, with an asexual and a sexual phase, and its robust resting spores make it difficult to control.