Objective The research aims to investigate the inhibitory effects of different Chinese herbal medicine extracts on banana Fusarium wilt, and to screen effective plant resources for the control of banana Fusarium wilt.

Method Tests were carried out on 29 Chinese herbal medicines, including Rheum palmatum and Andrographis paniculata, and the effective active ingredients were extracted by ethanol extraction. The inhibitory effects of different extracts on Foc TR4 were detected by the growth rate method, and the ethanol extracts of Rheum palmatum were extracted by using four solvents with different polarities, namely, petroleum ether, chloroform, ethyl acetate and n-butanol. The inhibitory effects of the extracts on the spores germination of banana Fusarium wilt were determined by the pendant drop method, and the effects of the extracts on the mycelial morphology of banana Fusarium wilt were observed.

Result The inhibitory effects of 29 herbal medicine extracts on Foc TR4 showed great differences, and four extracts, including Rheum palmatum, Andrographis paniculata, Sophora flavescens, and Chrysanthemum indicum had better inhibitory effects on Foc TR4, among which the best inhibitory effect was achieved by Rheum palmatum extract, with the inhibitory rate of 6 mg/mL Rheum palmatum extract being 48.57%, and the EC₅₀ of the mycelial growth being 6.68 mg/mL, while the EC₅₀ of the spore germination was 4.60 mg/mL. Through observation by light microscope, the Rheum palmatum extract had a certain destructive effect on Foc TR4 mycelium, which produced a large number of branches and adhesions and caused uneven mycelial growth; among the four extraction fractions of the ethanolic crude extracts of Rheum palmatum, namely, petroleum ether, chloroform, ethyl acetate and n-butanol, the extract fraction of ethyl acetate showed the best inhibitory effects on the growth and spore germination of Foc TR4 mycelium, and the inhibition rate of mycelial growth could reach 85.68% when the concentration was 10 mg/mL. The EC₅₀ value of ethyl acetate extract fraction of Rheum palmatum extract on Foc TR4 was 0.16 mg/mL.

Conclusion The Rheum palmatum extract was screened out from 29 Chinses herbal medicine extracts with better inhibitory effect, and its main effective inhibitory component against banana Fusariu wilt Foc TR4 was in the ethyl acetate extract fraction was further clarified, which could provide a reference for the research and development of new pesticides from plant resources for the prevention and control of banana Fusarium wilt.