Fungi for Controlling Soft-rot Disease on Taro

  Objective  Various fungi with a potential to be used for controlling the soft-rot disease on Fuding taro, Colocasia esculenta L. var. comosus Chang, were investigated.

  Method  Twenty-two fungal strains were isolated from rhizosphere soil and corms of healthy taro plants. Nine of them showing an in vitro antagonistic effect on the disease were selected. Molecular sequencing, morphological observation, physiological and biochemical characterization in the laboratory as well as a field test were conducted on them to screen for applicable candidates.

  Result  Fungal strains under the coded names of CAF-H001 and CAF-L002 exhibited a desirable control effect on taro in the laboratory. The ITS1/ITS4 sequences of the two strains were amplified and compared with NCBI database to show a 100% homogeny of CAF-H001 with Fusarium fujikuroi and of CAF-L002 with Aspergillus tubingensis. CAF-H001 had white mycelia and sickle-shape conidia that grew optimally at pH 9 and 28℃ on starch for carbon and peptone for nitrogen sources. Whereas, CAF-L002 had black mycelia and spherical conidia that preferred pH 8, 32℃, starch, and yeast extract.

  Conclusion  It appeared that CAF-H001, Fusarium fujikuroi and CAF-L002, Aspergillus tubingensis, could potentially be applied for controlling the soft-rot disease on taro.