Inhibitory Effect Of Common Plant Essential Oils On Several Plant Pathogenic Fungi

Essential oils are important secondary metabolites of plants,which have shown great potentials on antimicrobial functions due to their diverse bioactivities,innovative mechanisms,pure naturalness and pollution-free characteristics.In this paper,the antifungal activity of 4 kinds of common plant essential oils on 9pathogenic fungi was evaluated by means of mycelium growth rate method.By soaking seeds and several kinds of fruits into the oil solution,determines the effect of oil treatment on germination of crop seeds and its effect on the preservation of different fruits and vegetables.Results are as follows:?1?The antibacterial effect of 4 kinds of plant essential oils and 10 kinds of fungicides on common plant pathogenic fungi showed that the essential oils was better than that of most test chemical fungicides.The EC₅₀value of plant essential oils was 0.851-28.063 mL/L,there were not large differences between each oils while the EC₅₀ value of chemical fungicides were as large as 2.044 to 23556.681 mg/L.?2?The antimicrobial activity of 4 plant essential oils on 6 common plant pathogens was determined by double-dilution method.The MIC of lavender essential oil against Fusarium oxysporum,Verticillium dahliae,Rhizoctonia solani,Alternaria alternata,Pyricularia oryzac and Alternaria solani was:6.0?L/mL?5.5?L/mL?3.0?L/mL?4.5?L/mL?5.5?L/mL and 5.0?L/mL,respectively;The MIC of peppermint essential oil was:6.0?L/mL?5.5?L/mL?6.0?L/mL?5.5?L/mL?5.5?L/mL and 5.5?L/mL,respectively;The MIC of lemon essential oil was:20.5?L/mL?12.5?L/mL?9.0?L/mL?12.0?L/mL?20.5?L/mL and 20.5?L/mL,respectively;The MIC of grapefruit essential oil was:32.0?L/mL?33.5?L/mL?33.0?L/mL?31.0?L/mL?31.0?L/mL and31.0?L/mL,respectively;arrange them in the order of antimicrobial activity is lavender essential oil>mint essential oil>lemon essential oil>grapefruit essential oil.?3?Selected fungicides and plant essential oils were tested on crop seeds to determine the germination by petri dish germination method.The result demonstrated:that the crop seeds treated with essential oils the physiological indexes of seed germination were low.The germination and growth of pot culture,wheat and rice were well promoted which treated with 6 fungicides.The results suggested that the plant essential oil did have good antibacterial effect,but it was not suitable for seed treatment.?4?Study of the antifungal activity of 4 plant essential oil on Alternaria,Alternaria kikuchiana and Botrytis cinerea showed:4 plant essential oils had better inhibitory effects cause common pathogenic fungi diseases of fruits and vegetables on all 3 pathogenic fungi,and the antibacterial effect increased with the increase of plant essential oil concentration.Arrange them in the order of bacteriostatic activity is lavender essential oil>peppermint essential oil>lemon essential oil>grapefruit essential oil.?5?Plant essential oil treatment on fruits and vegetables preservation showed that the selected three kinds of essential oils had different degrees of antisepsis effect,could significantly inhibit the decay of cherry,tomatoes and grapes under high indoor temperature and high humidity.The lavender essential oil and peppermint essential oil could inhibit mycelial growth of Alternaria kikuchiana and reduce the decay percentage of pear.The deterioration percentage of the pear was 100 percent without the treatment of the 2 essential oils,while the percentage of the pear was reduced to 3.33 percent when the concentration of lavender oil was 1000?L/L.The antibacterial effect of the peppermint oil was even stronger at the concentration of 1000?L/L,completely inhibited the decomposition of the pear.