Control of pathogenic fungi on Panax notoginseng by volatile oils from the food ingredients Allium sativum and Foeniculum vulgare

To screen natural drugs with strong inhibitory effects against pathogenic fungi related to P. notoginseng, the antifungal activities of garlic and fennel EOs were studied by targeting P. notoginseng disease‐associated fungi, and the possible action mechanisms of garlic and fennel EOs as plant fungicides were preliminarily discussed. At present, the antifungal mechanism of EOs has not been fully established. Therefore, understanding the antifungal mechanism of plant EOs is helpful to address P. notoginseng diseases continuous cropping disease‐related obstacles and other agricultural cultivation problems. First, the Oxford cup method and chessboard were used to confirm that the EOs and oxamyl had a significant inhibitory effect on the growth of Fusarium oxysporum. F. oxysporum is the main pathogen causing root rot of P. notoginseng and the preliminary study on the antifungal mechanisms of the EOs against F. oxysporum showed that the inhibition of EOs mainly affects cell membrane permeability and cell processes and affects the enzyme activities of micro‐organism, to achieve antifungal effects. Finally, an in vivo model verified that both two EOs could significantly inhibit the occurrence of root rot caused by F. oxysporum. Significance and Impact of the Study: Fusarium oxysporum is the main pathogen causing root rot and continuous cropping disorder of Panax notoginseng. It is urgent to find natural antimicrobial agents from plants to control this disease. Our study found that garlic and fennel essential oils (EOs) had significant inhibitory effects on the pathogens of P. notoginseng diseases, and the EOs could achieve the antifungal effects by affecting the biological processes such as cell membrane permeability, cell process and sterol biosynthesis. Therefore, garlic and fennel EOs have the potential to be developed as natural antifungal agents and preservatives.