Isolation, Identification, Biological Characteristics, and Fungicide Toxicity of Atractylodes Root Rot Pathogen

  Objective  Pathogen that caused the root rot on Atractylodes macrocephala at Xinyang, Henan Province was isolated, identified, and studied for prevention and control of the disease.

  Method  Morphological and multiple gene analyses were employed to identify the pathogen. Biological characteristics of the isolate were determined.

  Result  The isolate had white hyphae, oval spores with slightly pointed ends, macroconidia sized (7–10) μm× (3–4) μm with 3–5 septa, and microconidia sized (3–5) μm × (1–2) μm with two or no compartments. It showed a high homology with Fusarium fujikuroi and was, for the first time, identified as the fungal pathogen responsible for the root rot disease on Atractylodes macrocephala. It thrived at 28 ℃, pH 7, sucrose for carbon, and potassium nitrate for nitrogen. Of the 3 plant-based fungicides tested, 0.3% eugenol soluble agent exerted the greatest toxicity on the isolate with an EC₅₀ of 6.906 mg·L⁻¹.

  Conclusion   F. fuciformis was identified as the pathogen that caused the root rot disease on A. macrocephala in Henan. The optimal culture conditions for the fungus included 28 ℃, pH 7, sucrose as the carbon source, and potassium nitrate as the nitrogen source.