[Pathogen identification of Pinellia ternata tuber disease and selection of fungicide].

The rotten tuber of Pinellia ternata was found as an important disease during the growing season in Tianshui production area. The isolated pathogens were tested following Koch's postulates and identified as Fusarium oxysporum. The suitable growth conditions for the F. oxysporum were 15-30 degrees C, pH 6-8, the optimal condition was 21.9 degrees C and pH 7.2. Some fungicides were demonstrated to be effective to inhibit the pathogen growth. 70% thiophanate-methyl and 58% metalaxyl MZ were most effective to inhibit the pathogen. The EC50 were 0.002 7, 0.066 2 g x L(-1), respectively.