不同除草剂对杂草土大黄的毒力和选择性研究

Study on the toxicity and selectivity of Herbicides to Rumex nepalensis

土大黄Rumex nepalensis Spreng是中国云南滇西北高山牧场的一种蓼科多年生杂草，通常被看作是牧场退化的重要表现之一。试验通过使它隆、快灭灵和双酯灵等10种除草剂对该物种的毒力和选择性测定分析，研究了土大黄不同生育期对除草剂的敏感性和应用后不同时期的中毒情况。结果表明：土大黄不同叶龄期对除草剂的敏感性不同，除草剂应在5叶期前应用，且2～3叶期效果最好；土大黄对各除草剂的中毒速度也存在显著差异，以百草枯和快灭灵效果最快；对土大黄的活性较高的除草剂为苯磺隆，龙拳，快灭灵和烟嘧磺隆。其中快灭灵、双酯灵和苯磺隆的选择性指数较高，应用后对其它物种影响相对较小，对黑麦草等禾本科植物安全。

Rumex nepalensis Spreng is a kind of weed in Alpine cangeland in northwest Yunnan province. It is usually considered as an important representation of grassland degradation. The effect and selectivity of ten kind of herbicide were studied in laboratory bioassay and field experiment. The results showed that the invasive specie had different sensitivity to herbicide at different growth stage, herbicides should be applied before 5 leaf-stage,and had the best effect at 2 -3 leaf-stage. The toxic velocity ,effect and sensitivity is different among these herbicide ,4 kind herbicides ,tfibenuron-methyl ,clopyralid carfentrazone -ethyland nicosulfuron had good effect on Rumex nepalensis. The selectivity of carfentrazone-ethyl ,Metostrey and tribenuron-methyl were higher with less influence on other speeies,and safe to gramineous vegetable such as ryegrass.