Herbicidal Activity,Mechanism Andapplication Of Pyrimidine Analogs In Rice Fields

In this research,the herbicidal activity,action mechanism andapplication of pyribenzoxim analogs were studied by pot bioassay in greenhouse,field experimengts and conventional biochemical methods.We ascertainedtheir herbicidal activity,and systematically studied ZNQ-17130 and ZNQ-17131,including their herbicidal activity,spectrum of weedcontrolling,activity to E.crusgalliat different ages,safety of different varieties of rice,selectivity between crops and weeds,appropriatetime,application technology and so on,in addition,explored the mechanism of some compounds.It providesacademic foundations for the commercial development and application of pyribenzoxim analogs.The results could be summarized as follows:The results ofbioassay by pot-cultureingreenhousemethod showed that pyribenzoxim analogs hadexcellent bioactivity to E.crusgalliat 50 ppm,the inhibition rates on E.crusgalli were 87.31?93.18%.The precision toxicity tests showed that the IC₅₀ values of pyribenzoxim analogs on E.crusgalli were ranged from 1.1237 to 8.7341ppm.The results of target enzyme assay revealed that ZNQ-17117,ZNQ-17118,ZNQ-17123,ZNQ-17124,ZNQ-17130,ZNQ-17131 and pyribenzoxim had inhibitoryeffects on ALS,and the I₅₀ values were 6.68,21.40,5.28,18.07,18.12,63.09andrespectively.Spectrum of weed controlling was carried by pot bioassay in greenhouse.Resultsshowed that ZNQ-17130 and ZNQ-17131 had good control effect to E.crusgalli,S.viridis,C.difformis,L.procumbens,A.retroflexus,P.oleracea,C.argentea and S.nigrum,and had special effect on E.crusgalli,the fresh weight inhibition rates were 100%,at 4.69?75 g a.i/hm².However,the sensitivity of E.indica and L.chinensis to ZNQ-17130 and ZNQ-17131 was poor.The sensitivity of E.crusgalli at different ages to ZNQ-17130 and ZNQ-17131 was determined by pot bioassay in greenhouse.Result showedthat E.crusgalli at 2.5 to 5.5leaf stage were very sensitive to ZNQ-17130 and ZNQ-17131.At 37.5?75 g a.i/hm²,E.crusgalli at 6.5 leaf stage was still sensitive to ZNQ-17130 and ZNQ-17131,butthe sensitivity decreased in other doses.The research of safety to various rice varieties by pot-culture in greenhouse method showed that the plant length and fresh weight were inhibitednotablelyas the rice was treated with ZNQ-17130 and ZNQ-17131respectively at 45 ga.i/hm²,and the inhibition to various rice varieties was significantly different.The Xiuzhan 15 and Ejingnuo 6had astrongerresistence to ZNQ-17130 and ZNQ-17131 while Xiushui123 was more sensitive.At 1.17-37.5ga.i/hm²,ZNQ-17130 and ZNQ-17131 had obvious inhibition effects and showed safety on Xiuzhan 15,Ejingnuo 6 and Xiushui 123.ZNQ-17130 and ZNQ-17131 had excellent selectivity between three kinds of rice and E.crusgalli.The order of safety to three kinds of rice is:xiuzhan 15>Ejinnuo 6>Xiushui 123.The results of field experiments showed that ZNQ-17130 and ZNQ-17131 had good safety to rice and could effectively control common weeds in the field at 15-60ga.i/hm²,and the effect of ZNQ-17130 and ZNQ-17131 to E.crusgalli,L.procumbens and C.difformis was better than L.chinensis.ZNQ-17130 and ZNQ-17131can be used in rice field to control E.crusgalli,broadleaf and sedge weeds.When E.crusgalli is 2-3leaf stage,broad-leaved weeds and Cyperaceae weeds are 2-4 leaf stage,and rice in 3leaf stage,ZNQ-17130 and ZNQ-17131can besprayed at 30-37.5ga.i/hm²adjusted to deliver 600 L ha^-1.