The Application Research Of Isoxaflutole In Corn

In recent years,Due to long-term use of traditional herbicides,the problem that the succession of weed communities,herbicide phytotoxicity to corn weed and resistance in corn field of China Emerge in endlessly,And there have significant difference in dominant weed species of corn field in our country.So the traditional herbicide cannot meet the needs of controling the weed,so new herbicides need to be developed and to be test for promotion.Isoxaflutole belong to the herbicide of HPPD inhibitors,is a pre/post emergence treatment herbicide which can be appiyed in soil treatment before sowing after emergence and foliage treatment after seeding.It have very good control effect for most gramineous and broadleaved weeds on corn field.Because of the advantages of wide control spectrum,quick effect and safety for crop and environmental friendly,it has been used in some countries in large areas.This herbicide in our country has not been promoted currently.Due to the difference between planting patterns and varieties,it is necessary to be explored in our country to see that it can be applied in the corn field of China or not.In this article,herbicidal activity of isoxaflutole,herbicide phytotoxicity to corn and the selectiveity between corn and weeds has been preliminary test form two ways that soil treatment before sowing after emergence and stem leaf after seed sprouting.In addition,there carrying out field efficacy trials of single isoxaflutole and with its mixtures,in oder to provide the references and basis for its application in the corn field of China.The results of the study are as follows:1,The result of herbicidal activity with pot-culture indoor shown that under the test dose,isoxaflutole both has high control effect on a variety of gramineae and broad-leaved weeds appiyed with pre/post-emergence treatment.Except Cyperus rotundus,isoxaflutole is much better compared with mesotrione in the control effect of Setaira viridis,Eleusine indica and Portulaca oleracea under two processing methods.different oxazole grass ketone in two kinds of processing methods,two different doses of green bristlegrass,eleusine indica,purslane control effect is much better than that of the contrast agents nitrate ketone sulfone grass.Under the test dose of 30 g.a.i./hm² with pre-emergence treatment,their fresh weight inhibition rate were 87.25%,96.15%,98.30%,but their fresh weight inhibition rate are only 53.47%,38.90% and 57.13% under the same dose of mesotrione.2,Results of bioassay of isoxaflutole to the seedling phase various corn varieties by potculture method shown that: under the two methods of pre/post-emergence treatment,isoxaflutole There has different degree of inhibition in maize seedling plant height of 21 different varieties.But under the recommended dose,isoxaflutole was safe for each variety of corn.With pre-emergence treatment under the dose of 110 g.a.i./hm² of isoxaflutole,the result shown that Jinwang3,Jundan29 had a relatively strong resistance with their plant height inhibition rate 1.93% and 2.82%;In relative,Lubainuo no.1 and Zhengdan 958 were sensitive to isoxaflutole;Under the dose of 220 g.a.i./hm² of isoxaflutole,Denghai 661,Denghai 6213,Denghai no.3,these three varieties were relatively sensitive,their plant height inhibition rate are 19.93%,18.16% and 19.93%.With post-emergence treatment under the dose of 100 g.a.i./hm² of isoxaflutole,the plant height inhibition rates of the tested 21 varieties of corn were between 1.69% 1.69%,which shown relatively safe;While under the dose of 200 g.a.i./hm²,Denghai 661,Ludan984,Jinwang3,Denghai605,Denghai 6213 and Ziyu no.2 are more sensitive,their leaves appear obvious albino symptoms and their plant height inhibition rate is between 12.31% 14.56%.3,Sandy culture method showed isoxaflutole had different degrees of inhibition on taproot length of corn seeding in the tested 9 kinds,in which Denghai no.3 and Lainong14 are more sensitive to it with their IC₅₀ respectively 1.57and1.98.Ludan 984,Liaoyu19 and Zhengdan958 appeared high resistance to isoxaflutole.Their IC₅₀ respectively are 4.07,4.72,5.15.The value of IC₅₀ of the resistant variety of Zhengdan958 is approximately 4 times the sensitive variety of Denghai no.3.4,The determine of indoor selective factor shown that The selectivity index of isoxaflutole between Zhengdan958 and two weeds that Eleusine indica and Portulaca oleracearespectively were 8.76,9.22 under pre-emergence treatment,far greater than 2;while under post-emergence treatment the selectivity index between corn and two weeds which were Echinochloa crusgalli and Portulaca oleracea respectively were 1.40,1.79,less than 2.This means isoxaflutole has very high herbicidal activity on Echinochloa crusgalli,Eleusine indica and Portulaca oleracea.And it used with pre-emergence treatment,the security is relatively higher than the treatment with post-emergence.5,The field efficacy trials shown that under two kinds processing method that pre/ postemergence treatment,isoxaflutole used alone and its mixtures both have good weed control effect on the common gramineous and broad-leaved weeds in the corn field.In addition to the treatment under the dosage of 75 g.a.i./hm² of it with stem leaf processing after 15 d,the total plant control effect 78.2%,the total plant control effect and fresh weight control effect are above 80%.The control effect of isoxaflutole used in mixture is better than used alone.Under the recommended dose,isoxaflutole has high security for corn.Isoxaflutole alone and in combinations used in corn field has good yield-increasing effect.