| Wheat head blight,caused by Fusarium graminearum,is the most important disease in wheat in Jiang-gang farm.It not only decreased wheat yield,but also decreased wheat quality,which seriously threatened wheat production.Chemical control is the most important measure to control this disease at present.After application of carbendazim or its mixture year by year,the resistance of Fusarium graminearum to carbendazim has become a common problem.It is urgent to screen the substitute for carbendazim.Wheat sharp eyespot is a disease of wheat stem base.It was be mainly controlled by spraying in spring in the past,but the efficacy was unstabitily.In order to sustainably manage the resistance of Fusarium graminearum,effectively control wheat sharp eyespot,the occurrence characteristics of wheat head blight and wheat sheath blight in Jiang-gang Farm were investigated.The mixed formula of fludioxonil plus tebuconazole/hexaconazole was screened.The screening of fungicides for controlling wheat scab,the demonstration test of mixing agents and technical scheme were carried out.The efficacy of tebuconazole seed treatment against wheat sheath blight was preliminarily studied.The main results are as follows:The results of the investigation from 2016 to 2018 showed that the occurrence of wheat scab was different among varieties in Jiang-gang Farm.Although most of them were Yangmai varieties and Ningmai varieties,the incidence was relatively low.Among them,Yangmai 13 variety and Yangmai 15 variety had higher incidence than other varieties.During the heading and flowering stage of wheat,the occurrence of fusarium head blight will be aggravated by cloudy and rainy weather.In the early November,the incidence of sharp eyespot was less than that of mid seeding.The distribution of wheat sheath blight was uneven in all divisions.The occurrence of wheat sheath blight in the 2nd and 4th division was more serious than that in others,and the occurrence in the 7th division was lighter.In the field screening test of fungicides,the control efficacy of phenamacril,tebuconazole and carbendazim were the best against wheat scab,and the control efficacy was about 80%.The results of the demonstration test were carried out with 2 solutions form these funigicides,the percentage of diseased panicles of wheat scab adopted solution 1(tebuconazole + carbendazim,phenamacril)and solution 2(tebuconazole + carbendazim,tebuconazole+ phenamacril)were significantly lower than those of carbendazim twice.There was no significant difference compared to that of the application twice of tebuconazole prochloraz(solution 3).The results showed that the three technical schemes were effective in controlling Fusarium head blight.The formulations of fludioxonil mixed with tebuconazole or hexaconazole against wheat scab were screened with carbendazim-resistant strain.The results showed that the optimum ratio of fludioxonil vs tebuconazole was 1:1,and it was 1:1 in fludioxonil vs hexaconazole too.The interaction of two components of fungicide mixture against wheat scab pathogen was additive.The results of field experiment showed that the control efficacy of fludioxonil plus tebuconazole(7.5 + 7.5)g/667m2 against wheat scab could reach 97%at the 14th day after application,and still was over 80%at the 21st day after application.The results showed that the mixture of fludioxoni and tebuconazole could effectively control fusarium head blight,especially in areas with high proportion of carbendazim-resistant population.The results of controlling wheat sheath blight showed that the control effect of 60 g/L tebuconazole SC 0.6-0.8 mL/kg(seeds)was more than 70%at the early March of the next year.When the dosage exceeds 1.2 mL/kg seeds,the emergence of wheat would be affected. |
