A study is presented of the reaction of potato varieties to the powdery scab due to Spongospora subterranea.
This disease has been observed since 1932 and the losses it causes are very reavy in the potato crop of the cool and rainy region, especiaily of Osomo, Llanquihue and Chiloé.
The means of controlling the disease bycrop rotation and cultivation of disease resistant varieties is analized.
Literature on the fungus in Chile and other american countries is reviewed.
The investigation carried out at Centinela has covered several hundred imported and domestic varieties and seedlings that were tested in a soil heavy infested with the Spongospora subterranea.
The reaction was evaluated taking into consideration the area covered by pustules and the degree of their development.
The most promising varieties are: Erie and Teton, followed by the seedlings C182-79, C64-4, C67-2, C99-1, C110-9 and C204-2.
The imported and domestic varieties tested and found susceptible to the disease are enumerated.
Susceptible seedlings are not listed.

1 Ingeniero Agronómo, Jefe de la Sección Plantas Industriales y Hortícolas. Departamento de Investigaciones Agrícolas, Ministerio de Agricultura.