40%砜吡草唑悬浮剂的除草活性及对花生的安全性评价

为明确砜吡草唑在花生田应用的可行性, 采用整株生物测定法测定40%砜吡草唑悬浮剂对马唐Digitaria sanguinalis、狼尾草Pennisetum alopecuroides、稗Echinochloa crus-galli、藜Chenopodium album、反枝苋Amaranthus retroflexus及马齿苋Portulaca oleracea的除草活性, 评价药剂对花生的安全性, 并利用田间小区药效试验进行验证。结果表明:40%砜吡草唑悬浮剂对6种供试杂草均表现出极高活性, GR 50为0.76~2.90 g/hm 2, 在13.32 g/hm 2剂量下, 对供试杂草防效均达100%。40%砜吡草唑悬浮剂对3种禾本科杂草、3种阔叶杂草的毒力分别是960 g/L精异丙甲草胺乳油的5.60~9.30倍和22.16~25.24倍。在盆钵底部渗灌、喷淋浇水2种灌溉条件下, 40%砜吡草唑悬浮剂对花生的GR 10分别为212.03、87.68 g/hm 2, 剂量越高, 对花生生长的抑制愈明显, 对花生安全性欠佳。在盆钵底部渗灌条件下, 砜吡草唑在花生和供试杂草间的选择性指数为29.45~142.30, 具有较高选择性。田间试验表明, 40%砜吡草唑悬浮剂施用剂量120~240 g/hm 2时, 对杂草的总体防效在92.6%以上, 花生增产率21.09%~22.71%, 杂草防效及花生产量均显著高于960 g/L精异丙甲草胺乳油720 g/hm 2处理, 所有药剂处理未见药害症状。综上, 40%砜吡草唑悬浮剂可作为花生田低量、高效化学除草的备选药剂, 但需关注砜吡草唑过量施用及降雨积水等因素导致的花生安全性问题。

Herbicidal activity of pyroxasulfone 40% SC on weeds and its safety evaluation on peanuts

To determine the feasibility of the pyroxasulfone applying in peanut field, the herbicidal activity of pyroxasulfone 40% SC on Digitaria sanguinalis, Pennisetum alopecuroides, Echinochloa crus-galli, Chenopodium album, Amaranthus retroflexus and Portulaca oleracea was determined by whole plant assay, and the safety of the pesticide on peanut was evaluated through field trail. The results showed that pyroxasulfone 40% SC showed very high activity against the six tested weeds, with GR 50 value of 0.76－2.90 g/hm 2 and control efficacy of 100% at 13.32 g/hm 2. Toxicity of pyroxasulfone 40% SC to three gramineous weeds and three broadleaf weeds was 5.60－9.30 times and 22.16－25.24 times of S-metolachlor 960 g/L EC, respectively. GR 10 values of pyroxasulfone 40% SC were 212.03 g/hm 2 and 87.68 g/hm 2, respectively under the two watering methods, watering by bottom infiltration and spraying above the basin. The higher the dose, the more obvious the growth inhibition, indicating relatively poor safety of pyroxasulfone to peanuT. Even so, the selectivity index of pyroxasulfone was 29.45 to 142.30 between peanuts and weeds under the way of watering by bottom infiltration. Field trail showed that weed control efficacy was more than 92.6% when pyroxasulfone 40% SC at dose of 120－240 g/hm 2, and the yield increase rate of peanut was 21.09%－22.71%. The weed control efficacy and peanut yield were significantly higher than that of S-metolachlor at dose of 720 g/hm 2, and no crop injury was observed in all treatments. In conclusion, pyroxasulfone 40% SC can be used as an alternative herbicide for weed control in peanut fields, but it is necessary to pay attention to the peanut safety issues caused by excessive application of pyroxasulfone and rainfall water accumulation.