Biological Characteristics and Lab Toxicity Test Results of Plum Fruit Spot Pathogen

  Objective  Biological characteristics of the pathogen that caused the plum fruit spot disease, Fusarium fujikuroi, were studied. Various agents for effective control of the disease were tested in the laboratory.

  Method  Effects of culture medium, light exposure, temperature, pH, and carbon/nitrogen sources on the growth of F. fujikuroi were determined. Toxicities of 7 fungicides to the pathogen were compared with the mycelium growth rate method in the laboratory.

  Result  F. fujikuroi grew well on Czapek or PDA medium at pH of 7-8 and 25 ℃. The preferred carbon sources were starch and glucosaccharide, and those for nitrogen, peptone and sodium nitrate for the culture. Different light exposures did not significant affect the fungal growth. The 7 fungicides displayed significant but varying inhibitory effects on the mycelial development. Among them, 45% imidazolide WDG, 20% pyrathiazolide SC, and 30% prothiazolium OD showed high toxicities with EC₅₀ of 0.891 4, 0.9436, and 1.022 0 μg·mL⁻¹, respectively.

  Conclusion   The effects of temperature, pH, light exposure, and nutrients on the growth of F. fujikuroi were clearly shown by this study. The relative efficacies of 7 commonly available fungicides for controlling the plum fruit spot disease were compared.