Study On The Selection And Application Of Fungicides For Controlling Wheat Scab

Wheat scab seriously affects the yield and quality of wheat in China.In recent years,the incidence rate has gradually increased,and it has developed resistance to a variety of traditional fungicides.Scientific control of Wheat scab is of great significance for ensuring wheat yield and quality.In this study,10 different pesticides were sprayed during the flowering period of wheat,and the occurrence of Wheat scab was counted during the wheat ripening period.High-efficiency pesticides for Wheat scab were screened out,and the effects of application methods on the efficacy were discussed.details as follows:(1)Screening of pesticides for Wheat scabWith reference to the "Guidelines for the Field Pesticide Effectiveness Test of Pesticides",a piggyback electric sprayer was used to spray a total of 10 fungicides during the wheat blooming period.Prothioconazole dispersible oil suspension agent,17%azole ether·fluconazole suspension agent has a good overall control effect on Wheat scab.Next,the prevention effect(disease index prevention effect)was 87.57%,87.83%,and 85.56%,respectively.Taking into account factors such as field efficacy and control cost,30%prothioconazole dispersible oil suspension was selected to control Wheat scab,and the application method was studied.(2)Effect of application methods on the control of Wheat scab by 30%prothioconazole dispersible oil suspensionThis study explored the difference in the prevention and control effects of the 30%prothioconazole dispersible oil suspension used in the two planting drones and the knapsack electric sprayer.The results showed that at the dosage of 45 mL/667m2,after using a drone and a backpack-type electric sprayer to spray 30%prothioconazole dispersible oil suspension,the wheat disease rate was less than 7%;Compared with the electric sprayer,the two planting protection drones showed better control effects,the control effects were 90.16%and 94.81%respectively.The application of mechanical spraying control should use the maximum recommended dose,which will increase to a certain extent Prevention effect.(3)GC-MS analysis method for prothiazole in wheat plants and wheat grainsA high performance and sensitive liquid chromatography-tandem mass spectrometry(LC-MS)was developed to evaluate the degradation of wheat samples under mycotoxin contamination.The average recovery rate and relative standard deviation(RSDs)of propanthiazole and desulfurized propanthiazole were 76.05%～96.17%and 0.84%～14.38%respectively.The average recovery of the five mycotoxins was 85.82%～103.24%and RSDs was 1.82%～7.03%.The residual degradation of prothiazole in wheat plants and grains was studied under field conditions with different spraying equipment and different prothiazole preparations.The use method and formula all affected the degradation of prothiazole and the content of mycotoxin was lower than the national standard.(4)Inhibitory effect of test agents on mycotoxinsCollect the harvested wheat kernels and check the content of five major mycotoxins according to standard methods.The results of the study showed that DON and 3A-DON were found in the wheat grains of the blank control group,and their contents were 0.199 mg/kg and 0.027 mg/kg,respectively.DON was detected in the samples of 250 g/L powdery tebuconazole suspension,40%azole ether and fluconazole suspension,45%methylthio·hexaconazole suspension,and the contents were 0.025 mg/kg,0.035 mg/kg 0.037 mg/kg,the content of mycotoxins in wheat in the other treatment groups was below the detection limit.