The Antimicrobial Activity Of Tea Tree(Melaleuca Alternifolia) Oil And Preparation Of Its Emulsion In Water

Due to the climate, environment and mode of production changes, plant diseases are becoming more and more serious. Chemical Fungicides plays an important role on control of plant diseases, however, long-term usage of chemical fungicides would cause pesticide residues, environmental pollution, resistance of disease, human health problems and so on. The people pay much attention to pesticide residues problem, and hope urgently to develop a natural plant fungicide instead of chemical fungicide. Therefore, in this paper, the differences of antibacterial activity of the domestic introduction tea tree oil (TTO), which is from FuJian, NanNing, GuiZhou, JiAn respectively was evaluated by growth rate method. Tea of oil-in-water emulsions bactericide was developed, and field experiments were conducted in rape plant, lettuce, and zucchini. The main results were as follows:1. Activity determination of TTO and its main components:9kinds of plant pathogens, such as Pyricularia grisea Sacc, Phytophthora capsici, Gibberella sanbinetti, Gleosporium fructigenum Berk, Venturia nashicola, Fusarium oxysporum f.sp.lycopersici, Botrytis cinerea, Phomopsis vexans (Sacc.et Syd.) Harter, Cytospora mandshurica Miura were chosen as tested pathogens for determination of antibacterial activity in vitro by growth rate method. The EC50values of TTO to Fusarium oxysporum f.sp.lycopersici, Pyricularia grisea Sacc, Cytospora mandshurica Miura, Venturia nashicola., Gibberella sanbinetti, Botrytis cinerea, Phomopsis vexans(Sacc.et Syd.)Harter, Phytophthora capsici, Gleosporium fructigenum Berk were determined. The EC50values of Ji’an TTO to tested pathogens described above were118.61mg-L-1,207.58mg-L-1,215.81mg·L-1,279.88mg-L-1,405.98mg-L-1,422.46mg-L-1,446.57mg-L-1,468.20mg-L-1,829.56mg-L-1respectively; The EC50values of FuJian TTO to tested pathogens described above were349.67mg-L-1,450.91mg-L-1,1189.85mg-L-1,316.29mg-L-1,389.86mg-L-1,404.03mg-L-1,1140.65mg-L-1,441.37mg-L-1,335.51mg-L-1respectively; The EC50values of Nanning TTO to tested pathogens described above were259.81mg-L-1,217.35mg-L-1,2469.50mg-L-1,543.98mg-L-1,528.19mg-L-1,475.01mg-L-1,1814.65mg-L-1,539.78mg-L-1,600.95mg-L-1:The EC50values of Guizhou to that were273.47mg-L-1,502.33mg-L-1,232.04mg-L-1,454.51mg-L-1,433.05mg·L-1,436.14mg-L-1,831.42mg-L-1,540.66mg·L-1,721.47mg-L-1. The results showed that tea tree oil to9kinds of plant Germs had antibacterial effect; four origin of tea tree oil had better antibacterial effect on Fusarium oxysporum f.sp.lycopersici, Gibberella sanbinetti, Botrytis cinerea, Pyricularia griseu Sacc.2. Antibacterial activities of Terpinen-4-ol, r-Terpinene, a-Terpineol,1,8-Cineole in four origin of TTO to Cytospora mandshurica Miura, Venturia nashicola, Botrytis cinerea, Phomopsis vexans(Sacc.et Syd.)Harter, Phytophthora capsici, were determined by growth rate method and fumigating method. The results indicated that alpha terpinenes had strong antibacterial activity on Cytospora mandshurica Miura, Fusicladium sp., Botrytis cinerea, Phomopsis vexans(Sacc.et Syd.)Harter Phytophthora capsici,5kinds of plant pathogen Phytophthora capsici EC50respectively was124.91mg/L,151.13mg/L,218.23mg/L,269.91mg/L,296.60mg/L r-Terpinene,1,8-Cineole had no inhibition effect against the tested bacteria. The results of fumigation experiment showed that:γ-Terpinene,1,8-Cineole fumigation on four plant pathogens had no inhibitory effect. a-Terpineol fumigation, fumigation time does not increase with inhibition rate decreased, when0.5h inhibition rate was above80%, and in24h,48h,72h training uniform showed strong inhibition effect.3. The main component contents of Ji’an, Fujian, Nanning, Guizhou origin of TTO by gas chromatography were determined, the contents of Terpinen-4-ol were4.60%,33.05%,29.25%,31.50%respectively; the contents of a-Terpineol were21.23%,4.54%,5.16%,5.45%respectively; the contents of y-Terpinene were4.99%,15.84%,14.85%,16.74%respectively; the contents of1,8-Cineole were14.16%,5.43%,5.84%,6.22%respectively. Fujian, Nanning, Guizhou origin of tea tree oil components had some differences, but it had big difference compared with the Ji’an origin of tea tree oil. This difference may be caused by after introduction of Melaleuca alternifolia small species, different growth environment of mutated or different processing methods.4. TTO EW formulation development and quality perfonnance evaluation:taking tea tree oil as main component, through selection of emulsifier, dispersant, antifreeze agent, the tea tree oil EW preparation was developed:40%TTO,5%emulsifier dosage,3%other additives amount, with distilled water up to100%. On40%TTO formula EW indicators were determined, respectively, on the hot storage stability test, cold storage stability test, freeze-thaw stability and dilution stability experiment. Select results did not appear stratification, condensate oil, condensate water, precipitation, water emulsion preparation of tea tree oil the main component thermal decomposition rate was less than10%, which is consistent with the pesticide preparation of product standards and standardized quality perfonnance standard. 5. The control efficiency on Botrytis cinerea of4main components of TTO and TTO by fumigation treatment. The results showed:after TTO fumigation treatment, inhibition rate was20%-40%three days later, which showed the general antibacterial activity; high concentration fumigation tomato bacteriostatic effect, relatively lower concentrations than the inhibition effect was good. TTO emulsion after treatment, the fourth day in the15%-50%inhibition exhibited antibacterial activity; a fumigation of strong, high concentration soaking bacteriostatic effect relatively lower concentrations than the inhibition effect was good.6. The result of the field trials of TTO water emulsions showed that control efficiency of7d and14d for lettuce Botrytis cinerea was25%,0.3%respectively at the125times dilution of20%TTOEW; at the200times dilution of40%TTO EW, it was70.5%and29.9%respectively; at the200times dilution of42.5%TTO·iprodione EW and42.5%TTOl·ebuconazole EW, the control efficiency of7d and14d of the former was46.10%,5.3%; and that of the later was47.60%、52.8%respectively. The control agent50%iprodione SE’s control efficiency of7d and14d was16.70%,7.2%respectively at the500times dilution; application dosage with the dilution increased gradually, control effect reduced. The control efficiency of7d after usage of TTOEW was all better than that of the control agent50%iprodione SE. The control efficiency of14d after usage of40%TTO EW was better than that of the control agent. Hence, TTO EW had control effect on lettuce Botrytis cinerea, and TTO·tebuconazole had a better control effect.The control efficiency of7d and14d for zucchini cinerea was21.73%,23.90%;23.57%,27.90%;26.07%,10%respectively at the125,200,300times dilution of40%TTO EW and at the125,200,300times dilution of42.5%TTO·iprodione EW, that was60.67%,50.08%;44.13%,49.57%;16.57%,26.40%respectively; The control agent50%iprodione SE’s control efficiency of7d and14d was64.8%,20.67%respectively at the500times dilution; the result indicated that it was not significant for control efficiency at different times dilution of40%TTO EW at0.05level after Variance analysis; however, it was significant for42.5%TTO·iprodione EW.The control efficiency of7d and14d for Sclerotinia sclerotiorum (Lib.) de Bary was76.67%,70.10%;66.00%,74.57%;57.17%,44.97%respectively at the125,200,300times dilution of40%TTO EW and at the125,200,300times dilution of42.5%TTO·iprodione EW, that was71.57%,61.10%;47.03%,62.10%;39.40%,26.03% respectively; The control agent50%iprodione SE’s control efficiency of7d and14d was31.47%,25.70%respectively at the500times dilution; the result indicated that it was significant for control efficiency at different times dilution of40%TTO EW at0.05level after Variance analysis; And it was also significant for42.5%TTO·iprodione EW.It can be obtained from the test data; TTO EW had a better control effect than chemical pesticides iprodione. In view of the determination results, it showed that TTO for iprodione chemical pesticide bactericide had strong synergistic effect, Tea tree oil is natural plant oil on some sudden massive disease and incidence of severe disease control effect than the chemical effect. Therefore the development of tea tree oil and chemical fungicide mixture preparation will have greater application value.