| Septoria microspra Ellis.is the main diseases of Gentian.It has common occurrences,high incidence and results in big losses. Based on previous studies,this research investigated the Seed infection test and treatment technology,as well as prevalence and prediction of the disease. By analysing the seed treatment,agricultural control measures,seedling treatment,chemical fungicide control methods and Chinese medicine Control methods,effective control measures are established.Lastly,it established a basis for security medication in planting by looking into some of the methods of determining fungicidee residues and fungicidee residue limits for fungicides in Gentian.In this study,the incidence for the disease and prediction has been compared. By using CurveExpert software,disease index y and time t are paired to establish a mathematical model.Data is collected from different time during the year.It is found that the Mathematical simulation model is the most suitable model to reflect the relationships of the two indexes.The other influencing factors include seasonal changes and environmental conditions (temperature,humidity,rainfall) factor binding,application software,establishment of conditions of temperature,rainfall,and humidity.The regression equation:Y=-0.324X1 +1.486 X2-3.228X3-6.439 can be used as forecasting model. (Y is for the three-year. X1=temperature.X2=humidity X3=volumn index of rainfall).Studies on the Seed infection test and the treatment technology revealed that the most practical and most convenient way of seed testing is to carry out germination tests in Petri dishes. Hot water treatment in 50℃for 15 minutes and in 60℃for 5 minutes has less effect on gentian seeds germination and can kill pathogenic bacteria in Gentian seeds. Fungicide treatment with Pyrimethanil (diluted 500 times),Polyoxin (diluted 300 times),Mildothane (diluted 300 times),Difenoconazole (diluted 1000 times),Mancozeb (diluted 5000 times) can completely kill the pathogen,and seed germination rate is not affected too much. Gentian seed treatment of three kinds of Chinese medicine alcohol extracts showed that, when the extracts are more than 30%,the bacteriostatic effect can reach over 90%. Seed treatments with Chinese materia medica preparation is safe and environmental,and is can be used as modern environmental friendly fungicides.In this experiment,agricultural measures on control effect of Septoria microspra Speg were carried out in intercropping corn on both sides of Gentian with different spacing in the rows. The best control efficiency is up to 51.1% with 50cm spacing.Laboratory efficacy trials on 20 kinds of fungicides established the Toxicity regression equation and determined EC50 and EC100. Various fungicides have obvious inhibitory effect of Septoria microspra Ellis. 10%Difenoconazole has the strongest inhibition rate on Septoria microspra Speg and inhibit concentration is 0.97μg/ml, EC100 is EC100; The second best combination is 80% Mancozeb,3% Polyoxin,70%Mildothane,68% Gold MZ,25% propiconazole,40% Pyrimethanil,25% Azoxystrobin.Gentian field experiments used the most effective fungicides determined by Laboratory efficacy trials.seedling treatment:The results showed that, Pyrimethanil diluted 800 times has the best effect. The control effect is 70.3%. The control effect of Azoxystrobin diluted 500 times, Mancozeb diluted 400 times,Mildothane diluted 600 times,Difenoconazole diluted 1000 times is also acceptable.Seedlings are concentrated and disposing easily. It may receive a better control effect. Outcomes of different fungicides to control Septoria microspra Ellis. results showed that,Propiconazole diluted 1000 times has the best effect.The control effect of Gold MZ, Pyrimethanil, Difenoconazole, Mancozeb with 5% carboxymethyl cellulose,Difenoconazole with 5% 885 auxiliaries is another acceptable solution.By carrying out fungicides residues dynamic analysis with Propiconazole,Pyrimethanil and Mancozeb,it is concluded that though Propiconazole,Pyrimethanil Have not used before,they are very effective in controlling the disease.Through fungicides residues dynamic analysis to Gentian collected at different. times the maximum limits of pesticide and Safety standard is drawn up and Gas chromatographic method of Propiconazole and Liquid chromatographic method of Pyrimethanil in Gentian is established. Fungicides residues dynamic analysis result indicated that,form the forth time,Propiconazole residues is lower than MRL which is drawn up by U.S. Environmental Protection Agency. Pyrimethanil residues is still higher than MRL which is drawn up by U.S. Environmental Protection Agency after 22 days. |
PDF Full Text Request