吡草醚室内除草生物活性测定及对小麦安全性评价

为探讨原卟啉原氧化酶抑制剂类除草剂—吡草醚防除小麦田阔叶杂草的生物活性及其对小麦的安全性,采用室内生物活性测定法研究了吡草醚对我国北方小麦田常见5种阔叶杂草的除草活性及对3个小麦品种的安全性。结果表明:吡草醚对播娘蒿Descurainia sophia、荠菜Capsella bursa-pastoris和麦瓶草Silene conoidea的防效好,GR_(90)值分别为3.66、4.21、2.57 g(a.i.)/hm~2,对猪殃殃Galium aparine、麦家公Lithospermum arvense的防效略差,GR_(90)值分别为11.41、17.39 g(a.i.)/hm~2,其活性是苯磺隆的2.27~9.07倍;吡草醚对抗苯磺隆荠菜有一定的控制作用,GR_(90)值为47.55 g(a.i.)/hm~2。该药剂对小麦安全性好,当剂量为384、192 g(a.i.)/hm~2时,小麦出现轻微触杀性药害;济麦22、良星66和矮抗58对吡草醚的耐药性分别为对苯磺隆的2.00、2.41和1.18倍。吡草醚在供试3个小麦品种与5种杂草之间的选择性指数在22.80~309.73之间,优于苯磺隆。表明吡草醚茎叶喷雾处理对温室盆栽阔叶杂草具有速效性好、活性高、选择性强等优点,是具有开发前景的一种麦田除草剂。

Herbicidal activity and safety of pyraflufen-ethyl to wheat in glasshouses

Pyraflufen-ethyl is a protoporphyrinogen oxidase-inhibiting herbicide, registered in China in 2013. Dose-response experiments were carried out to determine its weed control effect and safety to three wheat varieties in glasshouses. The results showed that pyraflufen-ethyl could effectively control Descurainia sophia, Capsella bursa-pastoris, and Silene conoidea with a GR₉₀ of 3.66, 4.21, and 2.57 g (a.i.)/hm², respectively. Pyraflufen-ethyl could also control Galium spurium and Lithospermum arvenseat high dosage, with a GR₉₀ of 11.41 and 17.39 g (a.i.)/hm², respectively. The herbicidal activity of pyraflufen-ethyl was 2.27-9.07 folds as that of tribenuron-methyl. Pyraflufen-ethyl could also injure and inhibit the growth of C. bursa-pastoris,which had high resistance to tribenuron-methyl, with a GR₉₀ of 47.55 g (a.i.)/hm². Pyraflufen-ethyl had good safety to wheat, only causing slight injury to wheat when the dosage was up to 384, 192 g (a.i.)/hm². The tolerances of Jimai 22, Liangxing 66, and Aikang 58 to pyraflufen-ethyl were 2.00, 2.41, and 1.18 folds as that of tribenuron-methyl, respectively. The selectivity index of pyraflufen-ethyl between three tested wheat varieties and five species of weeds were from 22.80 to 309.73, which were also higher than that of tribenuron-methyl. Pyraflufen-ethyl had relatively high activity and selectivity when applied post-emergence.