Abstract
Field studies on the control of potato common scab were carried out using a Streptomyces scabies-antagonistic biofertilizer produced from swine feces with a selected strain of Streptomyces albidoflavus CH-33. The field soil, which was supplemented with lime in order to adjust the pH into the agricultural range of 6 to 7, was mixed with 3.8 kg of biofertilizer per subplot (1.0 × 1.2 m) to a depth of 15 cm. The scab severity, in terms of the percent coverage of the total surface area of the potato tubers, was 18.3 % and 23.2 % in the control and the subplot supplemented with barnyard manure, respectively, whereas the lesions were light in the biofertilizer subplot, the scab severity being only 1.7% in terms of percent coverage. The field soil supplemented with the biofertilizer gave the maximum potato production. In the biofertilizer subplot, the viable count of Streptomyces scabies in the field soil had decreased to 2 × 102 per gram soil by 80 days, whereas that of actinomycetes including Streptomyces albidoflavus CH-33 had increased to 4 × 108 per gram soil.
