Isolation and Identification of mulberry Fruit Rot Pathogens and screening of antifungal plant extracts

Objective In order to provide a basis for the green prevention and control of mulberry fruit rot disease, the pathogen causing fruit rot mulberry was isolated and identified, and plant extracts with significant antifungal activity were screened out.

Method The pathogenic fungi was isolated by tissue separation and identified by fungal morphology and molecular biology. The antifungal activity of 54 plant extracts was determined by mycelium growth rate method. The extracts with potent activity were selected and the virulence was measured by concentration gradient. At the same time, the influence of the active extracts on mycelium morphology was observed by microscope.

Result The pathogen causing mulberry rot disease was Mucor fragilis; at a concentration of 1 mg·mL⁻¹, the extracts of Artemisia caruifolia and Salvia uliginosa showed sinificant inhibitory effect on M. fragilis, and the inhibition rate was 77.72% and 49.06% respectively. According to the toxicity test results the antifungal effective middle concentrations (EC₅₀) of extracts of A. caruifolia and S. uliginosa were 0.063 mg·mL⁻¹ and 0.107 mg·mL⁻¹ respectively. Mycelium distortion was found by microscopic observation after treated with the extract of A. caruifolia and there was no change in the S. uliginosa.

Conclusion This study identified significant antibacterial effects of Artemisia caruifolia and Salvia uliginosa against M. fragilis, with A. caruifolia extract showing particularly strong activity (EC₅₀=0.063 mg·mL⁻¹). This suggests valuable potential for developing green control methods for mulberry fruit rot.