Tuber-borne infection in potato common scab disease and effect of soil sterilization and seed treatment on the control of the tuber-borne infection

Abstract

Tests carried out over a period of 5 years indicated the existence of tuber-borne infection in common scab of potatoes. When seed tubers in which more than 6% of the surface area was affected with scab were planted, the scab incidence in the progeny tu-bers was very high. When seed tubers in which less than 5% of the surface area was affected with scab were planted the scab incidence was very low and comparable to that when seed tubers devoid of lesions were planted. However in fields disinfected with chlorpicrin, although seed tubers in which 5% of the surface area was affected and seed tubers without lesions were planted, a severe incidence of the disease was observed. In non-infected fields, the application of copper compounds and streptomycin was effective in controlling scab while in fields which had been disinfected the effect of the application decreased.