A SOFT ROT OF SUGAR BEET AND ITS CAUSAL ORGANISMS

Abstract

The present paper deals with a bacterial rot of sugar beet which prevails over Heijô, nothern part of Korea, causing yellowish soft rot and producing odor peculiar to the disease. Inoculation experiments showed the pathogenicity on carrot root), radish (root), potato (tuber), and tomato (fruit).
The causal organism was compared with Bact. beticola, Bac. Betae, Bact. Serbinowi, specially Apl. teutlium, the causes of sugar beet diseases. And also comparison was made with Bac. aroideae, Bac. carotovorus and Bac. atrosepticus, the Causes of Vegetable diseases. No organism were found to be identical with the organism in question. Therefore, Bac. betivorus is proposed for the organism. A description of the organism is given as follows:
Bacillus betivorus n. sp.
A short rod with rounded ends, single, in pairs, or sometimes in long filaments in beef bouillon containing salts; motile by means of 2 to 6 peritrichiate flagella; Gram's negative. It forms no spores or capsules. It produces round or amoeboid homogenous thin colonies with smooth and entire margin on beef agar; clouds bouillon promptly and forms pellicle; liquefies gelatine; coagulates milk. It reduces nitrates; produces indol or hydrogen sulphide; produces gas from sucrose and glucose; is facultative anaerobic or aerobic. Optimum temperature for growth is about 35°C, min. at 12°C, max. at 45°C and thermal death point 50°C for 10 minutes.