为了寻找防除薇甘菊的高效药剂，本研究测定了2,4-滴微乳对外来入侵杂草薇甘菊的生物活性和田间防治效果。通过测定抑制率求取抑制薇甘菊生长90%的有效剂量ED90，以覆盖度防效和鲜重防效为指标研究其田间防治效果。盆栽试验结果表明：喷施后30天，18% 2,4-滴微乳剂(ME)抑制薇甘菊茎叶生长的ED90值是制剂用量125.9 mL/667 m2，抑制地上部和根部鲜重的ED90分别为制剂用量99.3 mL/667 m2和141.3 mL/667m2。在田间条件下，喷药处理后15、30天，供试18% 2,4-滴ME制剂用量60~180 mL/667 m2处理时覆盖度防效均为90%以上，显著优于或相当于70%嘧磺隆WP制剂用量25 g/667 m2处理防效。处理后45天时，18%2,4-滴ME制剂用量120、180 mL/667 m2对薇甘菊的鲜重防效均在90%以上，与70%嘧磺隆WP制剂用量25 g/667 m2处理防效差异不显著。供试18% 2,4-滴ME对薇甘菊选择作用明显，具有“灭薇保草”的效果，适用于林地、非耕地和城市绿化地防治薇甘菊，有利于受薇甘菊破坏的生态环境的保护与恢复。

The bioactivity and effect of 18% 2,4-D ME against Mikania micrantha were investigated through the potting and field tests in this paper, which was helpful for screening more effective herbicides against this species of alien invasive weed. The value of ED90 inhibited 90% of M. micrantha growth was calculated through the measurement of inhibition rate in the potting test, and the coverage control and fresh weight effectiveness was calculated to indicate the effect of 18% 2,4-D ME under field condition. The results of potting test showed that ED90 value in the 30th day was 125.9 mL/667 m2, which indicated 18% 2,4-D ME restrained the growth of M. micrantha’s stem and leaf, and ED90 about M. micrantha fresh weight of overground part and roots were 99.3 mL/667 m2 and 141.3 mL/667m2, respectively. The results in field experiment showed that the coverage control effects were more than 90% against M. micrantha after 15 and 30 days treatment with 18% 2,4-D ME from 60 to 180 mL/667 m2, which were significantly higher than that of 70% sulfometuron methyl WP in 262.5 g a.i./hm2, and were more than 90% after 45 days treatment with 120, 180 mL/667 m2 of 18% 2,4-D ME, which had no significant difference with that of 70% sulfometuron methyl WP in 262.5 g ai/hm2. All these results indicated 18% 2,4-D ME in this test had obvious choice on M. micrantha, which could kill M. micrantha and protect other weeds. The tested 18% 2,4-D ME could deserve to be applied to control M. micrantha in forest land, non-cultivated land and urban green land to protect and recovery of the ecological environment damaged by M. micrantha.