Studies On The Phytotoxiciy Of Wheat Caused By Mixture Of Herbicide Fluroxypyr And Triazole Fungicides

In recent years,the occurrence of Wheat Sheath blight has become more and more serious in Jiang-gang Farm,and the control of wheat sharp eyespot has been paid more and more attention.The time for controlling wheat sharp eyespot in spring is close to controlling broadleaf weeds in wheat fields.In practice,fungicides and herbicides are often mixed to reduce the cost of pesticide application.However,when mixed with herbicide fluroxypyr-meptyl and fungicide difenoconazole propiconazol,there was a phytotoxicity in wheat.In order to find out the safety of mixed with herbicides and fungicides on wheat;these had been done in pot experiment and field experiment in this paper.The safety of fluroxypyr-meptyl mixed with difenoconazole,tebuconazole,diniconazole and hexaconazole respectively on wheat was studied.The interval time between the safe application of fluroxypyr-meptyl and difenoconazole and its effect on the yield of wheat were discussed in field.The main results were as follows:Wheat cultivar,Ningmai 13,was sprayed with fluroxypyr-meptyl and triazole fungicides,such as difenoconazole,tebuconazole,diniconazole and hexaconazole respectively in 5-lesf-stage.Damage symptoms were showed obviously in Ningmai 13.The main symptoms were yellowing of wheat leaves.But when the phytohormone herbicide MCPA-sodium,other test herbicides was mixed with triazole fungicides respectively,there were safe to wheat.Ningmai 13 basal leaves showed yellowing symptoms at 5 days after treatment(DAT)with fluroxypyr-meptyl(288g/L EC)40-80 ml/667 m2 mixed with difenoconazole and tebuconazole,respectively.The symptoms of dead basal leaves or whole withered yellow were observed at 10 DAT and 15 DAT.The damage index of fluroxypyr-meptyl 80 ml/667 m2 mixed with difenoconazole was 96.19%in 20 DAT.The wheat grew normally without obvious symptoms of phytotoxicity at 25 DAT.When fluroxypyr-meptyl(288g/L EC)dosages of 40-80 ml/667 m2 mixed with diniconazole and hexaconazole respectively,the light-injury symptoms of wheat were only yellowing in the base leaves at 5 DAT,and there was no significant difference in the injury index between treatments,which were 2-3%.The injury index of fluroxypyr-meptyl(288g/L EC)40-80 ml/667m2,mixed with diniconazole and hexaconazole respectively was significantly different at 15 DAT.Wheat normally grew at 20 DAT.Difenoconazole(40%SC)doses of 20-30 ml/667m2 was applied at 0-10 days after the application of fluroxypyr-meptyl(288g/L EC)40-80ml/667m2 respectively,wheat injury occurred,and the higher the dosage,the higher the injury index.The mean 1000 grain weight,mean grains per panicle and theoretical yield of the four treatments,which difenoconazole(40%SC)doses of 25-30 ml/667m2 was applied at 0-10 DAT of fluroxypyr-meptyl(288g/L EC)60-80ml/667m2 applied,respectively,were significantly lower than those of the control,showing a reduction in yield.Interval 12 days application,the injury symptoms only showed at high doses both fluroxypyr-meptyl and difenoconazole,and low phytotoxicity index was showed,the theoretical yield was no significant difference compared with the control.