| Benzobicyclon,which targets the 4-hydroxyphenylpyruvate dioxygenase(HPPD),is a bicyclooctane herbicide.Eleusine indica,Monochoria korsakowii,Alternanthera philoxeroides,Aeschynomene indica,Parthenocissus tricuspidata,Cyperusdiffformis,Echinochloa crusgalli,Celosia argentea,Euphorbia lathyris,Eclipta prostrata,Commelina communis,Acalypha australis,Geranium carolinianum,Capsella bursa-pastoris,Alopecurus japonicus,Vicia hirsute Veronica persica and Rorippa globosa were collected in Anhui province.These 18 kinds of weeds and 8 rice varieties,including Wankennuo 1,Wandao 68,Lvhanjing 1,Longliangyouhuazhan,Wandao 119,C liangyou 608 and Huiliangyou 882,were used to study the controlling spectrum,safety of benzobicyclon to rice,field dosage and mixing with penoxsulam.The results of whole-plant bioassay showed that the aboveground fresh weight reduction of common weeds in rice field,including E.crusigalli,M.korsakowii and C.difformis,were all above 90%at active ingredient of 360 g/hm2.The GR50 value of benzobicyclon against main autumn weeds were 48-196 g/hm2.The biological activity of benzobicyclon was higher than that of mesotrione except in the case of A.indica.The safety of rice varieties to benzobicyclon was studied.At the rate of 720 g/hm2,the tolerance of Longliangyouhuazhan,Wankennuo 1,Wandao 68 and Lvhanjing 1 to benzobicyclon were good.However,the plant height and fresh weight of Huiliangyou 882,C liangyou 608,Wandao 119 and Y liangyou 1 were inhibited in different degree.Selectivity index of benzobicyclon between Longliangyouhuazhan,Wankennuo 1,Wandao 68,Lvhanjing 1 and three weeds were 3.66-4.37,4.50-5.37,3.36-4.01 and 3.29-3.93,respectively,which was much higher than that of mesotrione.Thirty and forty five days after benzobicyclon treatment(DAT),the plantand fresh weight controlling effect of common weeds in rice field,including E.crusgalli,C.difformis and M.korsakowii,were all above 85%at the rate of 210 g/hm2.The efficacies of mesotrione at the rate of 150 g/hm2 to E.crusgalli,C.difformis were lower than benzobicyclon at active ingredient of 210 g/hm2.There had a similar efficacies on E.lathyris and M korsakowii.The controlling efficacy of benzobicyclon at the rate of 270 and 420 g/hm2 were higher than mesotrione.Considering a variety of factors,the suitable amount of efficacy components in the field was 210-270 g/hm2.Meanwhile,the soil wettability should be maintained.The mixing of benzobicyclon and penoxsulam mainly showed a synergistic effecton weeds.The optimal prescription compositions about penoxsulam and benzobicyclon was the dose of 9 a.i.g/hm2 and 90-120 a.i.g/hm2,respectively.With the ratio of 1:10-13,the combination had a synergistic effect. |
