| Wheat stripe rust is a fungal disease that can occur throughout the growing season of wheat.Chemical control can quickly inhibit the growth and spread of wheat stripe rust in the short to medium term,and can achieve great results in prevention,treatment and eradication.This research will start from the basic method for establishing a fast and convenient effectiveness measurement system.Which can be used to evaluate the current status of triadimefon in controlling wheat stripe rust.By screening other fungicides and conducting field effectiveness tests,it will guide the formulation of field management technical rules and delay the risk of resistance and conduct resistance management.1 Establishment system for rapid quantification of fungicide effectiveness on inhibiting wheat stripe rust pathogen with detached leaves.The results showed that 0.5%water agar containing filter paper and 75μg/ml of 6-BA（6-Benzylaminopurine）worked the best for maintaining wheat leaves.The disease incidences of different concentrations of spore suspension were compared.When the spore concentrations were 5 and 10 mg/ml,the disease incidences had no significant differences at 12 and 15 days after inoculation（P<0.05）.Fungicide treatment tests revealed that there were no significant differences in the efficacies of triadimefon on rust suppression between detached leaves in the culture dishes and direct spray on seedlings.We also developed a Photoshop software method that can replace the current classification method and accurately measuring the proportion of sporulation area on infected leaves.2 Establishing the sensitivity baseline of wheat stripe rust to triadimefon.In order to determine the feasibility of the system obtained and the difference from the traditional pot method,the efficacy of triadimefon on Pst-39 isolate was measured.The results showed that the EC50 measured by the pot method was 2.2057μg/m L and the EC50 measured with detached leaves was 0.0821μg/m L.The detached leaves method is feasible and more sensitive than the pot method.The detached leaves method is feasible and more sensitive than the pot method.This method was used was used to measure the sensitivity of 81 isolates to triadimefon,and the EC50 range from 0.0015 to 0.3117μg/m L,with an average value of 0.1453±0.0081μg/m L.There are large differences between strains.Kolmogorov-Smirnov test showed that the obtained EC50 was normally distributed（D=0.2>0.05）.MIC measurement showed that 60μg/m L triadimefon can inhibit 99%to 100%of 15 strains with detached leaves method.3 Single-agent screening of wheat stripe rust.The effectiveness of 17 fungicides was measured with detached leaves.The results showed that pyraclostrobin and prothioconazole had the great effectiveness,with EC50 of0.0497 and 0.0919μg/m L,respectively.The relatively poor effectiveness was triclostrobin,whose EC50 was 2.8938μg/m L.The results of field single-agent fungicide effectiveness tests conducted in Chongqing in 2019 showed:The control effectiveness of 125g/L fluconazole SC（101.25g a.i./hm2）,25%pyrazoxystrobin EC（112.5 g a.i./hm2）,and 430g/L tebuconazole SC（99.94 g a.i./hm2）was significantly higher than other fungicides,with effects of 90.47%,80.14%and 79.55%,respectively.50%triclostrobin WG（270 g a.i./hm2）had a control effect of 60.92%and was not recommended for application.4 Screening of compounding fungicides of wheat stripe rust.The Horsfall method was used to screen the best combination of 99 combinations,and 25 kinds of compounding were obtained.The Wadley method was used to evaluate the combined virulence of 25 formulations,and a total of 4 formulations with SR>1.5were selected:prothioconazole and veracol（4:6）,prothioconazole and pyraclostrobin（3:7）,triazolone and azoxystrobin（2:8）,prothioconazole and verrucous Spirit（1:9）.The actual EC50 of the four formulations was less than 0.1μg/m L,which showed high virulence to Pst.The results of the field efficacy test of formulations conducted in Chengdu in 2020showed that:The prothioconazole and carboxin（1:9）（4:6）have reached a control effect of more than 95.00%at high,medium,and low doses,and have significant synergistic effects.The combination of prothioconazole and pyraclostrobin（3:7）has the highest control effect at 100 g ai/hm2 is 97.00%.The combination of triazodone and azoxystrobin（2:8）at the three doses had highest at a low dose of 150 g a.i./hm2,which was 98.82%.5 Field efficacy test of agricultural additive for controlling wheat stripe rust.The field test results of single-dose+“Yimanchu”showed that:in the case of a single-dose reduction of 20%and the adjuvant,pyraclostrobin（86.54%）and tebuconazole（85.11%）,azoxystrobin（83.03%）,triadimefon（76.28%）,the control effect is significantly higher than that at the recommended dosage;fluconazole（88.46%）,thiofuramide（75.17%）,tebuconazole（83.50%）)and the antimicrobial effect（59.33%）did not differ significantly from the recommended dosage.This shows that the additive"one-full removal"（625.05 g a.i./hm2）has reached the technical requirements for increasing the efficiency of the fungicide and can be used for practical control.And in the case of adding additives,fluconazole（81.00 g ai/hm2）,pyraclostrobin（90.00 g ai/hm2）,oxiconazole（67.50 g ai/hm2）,tebuconazole（79.95 g ai/hm2）,the control efficacy of azoxystrobin（216 g ai/hm2）is above 80%,and is recommended for field trials.The test results of the compounding agent+“Yimanchu”showed that the agricultural additive had no effect on the growth of wheat from the jointing stage to the filling stage.And for the four compounding agents prothioconazole and carboxin（1:9）（4:6）,prothioconazole and pyraclostrobin（3:7）and triadimefon and azoxystrobin（2:8）it had the same or higher significant control effect,which can achieve a fungicides reduction of more than 20%and the control effect can reach 90%or more. |
