Abstract:

In order to study on influence of fungicide on growth of Rhizopus stolonifer SP-1 and Hypocrea sp SP-4 of pathogenic bacteria of sweet potato, spores of Rhizopus stolonifer SP-1 and Hypocrea sp SP-4 isolated from spoilage root tuber of sweet potato were inoculated on PDA medium plate and root tuber of sweet potato including different concentrations of fungicide, and cultivated at 13℃ and 28℃. The results showed that they grew more slowly at 13℃ than 28℃. Dilution concentration of thiophanate-methyl and carbendazol to inhibit the growth of Hypocrea sp SP-4 and R. stolonifer SP-1 is 1000 and 500-fold, respectively. Both fungicides could efficiently inhibit the growth of Hypocrea sp SP-4. However, the inhibition rate of thiophanate-methyl and carbendazol to R.stolonifer SP-1 is 21% and 58%, respectively. The results also showed in the course of fungicide inhibiting the infection of root tuber of sweet potato by the above two fungi, it didn’t become rotten at low temperature if the root tuber of sweet potato did not have wound, indicating that they infect root tuber of sweet potato through the wound. Comprehensive analysis show that the infection of root tuber of sweet potato by fungi could be reduced by moderate low temperature and avoiding wound of sweet potato.