The Influence of Various Soil Factors upon Potato Scab Caused by Actinomyces scabies

Abstract

Scab, caused by Actinomyces scabies (Thaxt.) Giiss., is a potato disease of major importance in western Nebraska. Seed treatments are effective in controlling seed-borne scab, but it has been shown that even when healthy or treated seed potatoes are used the disease may be very severe because of infection from the soil. Crop rotation will reduce the incidence of the disease, but the fact that potato scab may cause serious loss in soils never before planted to potatoes indicates that there are numerous factors other than the time interval between potato crops which affect the occurrence of the disease. A study of many of these factors has been undertaken in the field, greenhouse, and laboratory and the present publication deals with some of the results obtained under partially controlled conditions in the greenhouse.