Herbicidal characteristics of herbicide-bipyrazone in wheat fields
To determine the optimal application conditions for the herbicide bipyrazone in wheat fields,we used Capsella bursa-pastoris(L.)Medic as the target to study the effects of various factors,includ-ing temperature,light intensity,rainfall intervals after application,and leaf stages of the weed on herbi-cidal efficacy under greenhouse conditions.The results showed that within a temperature range of 10 ℃to 35 ℃,the herbicidal activity of bipyrazone against C.bursa-pastoris significantly increased with in-creasing temperatures,with GR50 values ranging from 3.19 to 6.57 g(a.i.)/hm2.Light intensity also had a significant impact on bipyrazone's efficacy.Compared to moderate(45％light)and low(4％light)con-ditions,high light(100％light)significantly enhanced the control efficacy of bipyrazone,with fresh weight inhibition rates ranging from 59.80％to 89.72％.Rainfall also significantly affected the the con-trol efficacy of bipyrazone,but when the interval between rainfall after application exceeded 4 h,there was no significant correlation between herbicidal activity and the interval time,with GR50 values ranging from 4.28 to 4.50 g(a.i.)/hm2.Additionally,as the leaf stages of weed advanced,the herbicidal activity of bipyrazone decreased.Capsella bursa-pastoris at 1-3 leaf stages was most sensitive to bi-pyrazone,with GR50 values between 1.77 and 4.45 g(a.i.)/hm2.In conclusion,to maximize the herbicid-al effectiveness of bipyrazone,it is recommended to apply the herbicide on sunny days with tempera-tures above 15 ℃,when winter wheat is in the regreening to jointing stage,and when most broad-leaved weeds are in the 1-3 leaf stages.If broad-leaved weeds are beyond 4-leaf stage,the POST appli-cation rate of bipyrazone should be increased accordingly.Additionally,if rainfall occurs within 4 h af-ter application,a supplementary application is advised.
herbicides for wheat fieldbipyrazoneCapsella bursa-pastoris(L.)Medicfunctional characteristicenvironmental factor
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