Abstract:
Objective Pathogen of the fruit rot on mulberries was isolated and identified, and effective antibacterial plant extracts for the disease prevention and control selected.
Method Tissue separation method was applied to isolate potential pathogens from the infected mulberries. The morphology and molecular biology of the isolates were examined for pathogen identification. Antibacterial activity of 54 plant ethanol extracts was tested to compare the inhibition on the growth of the isolate mycelia. Virulence of the most potent extracts at gradient concentrations was determined along with microscopic observations.
Result Growth of the identified pathogen, Mucor fragilis was significantly inhibited at a rate of 77.72% by the extract of Artemisia caruifolia on a dosage of 1 mg·mL−1 rendering an EC50 at 0.063 mg·mL−1, and also at a rate of 49.06% by Salvia uliginosa with an EC50 at 0.107 mg·mL−1. In addition to a higher inhibition rate, the A. caruifolia extract induced significant mycelial distortions on the pathogens as shown under the microscope.
Conclusion Significant antifungal activities against the mulberry rot-causing M. fragilis were found of the ethanol extracts of A. caruifolia and S. uliginosa. With a toxicity of EC50 at 0.063 mg·mL−1 and significant deformation on the mycelia of the pathogen, A. caruifolia was considered the choice candidate as a biocontrol agent against the disease.