Abstract: Surface tension and spreading characteristics of drops of 0.5% emamectionbenzoate microemulsion(ME) on rice leaf were studied at concentrations of 0.78-12.50 mg/L. Results showed that the surface tensions of emamectionbenzoate ME at 156, 312, 625 and 1250 mg/L were smaller than the critical surface tension of rice leaf. The contact angles of the drops of these solutions were different when the drops were dropped onto rice leaf. However, as time went on, the contact angle diminished, and the diminishing speed increased with rising concentration. Finally, the drops that the surfactant reached the CMC (critical micelle concentration) in these solutions at 312, 625 and 1250 mg/L spread completely, whereas the drops that the surfactant did not reach the CMC in the solution at 156 mg/L could not spread completely. The surface tensions of emamectionbenzoate ME were smaller than the critical surface tension of rice leaf at 156-100 mg/L while the surface tension of the same concentration of emamectionbenzoate emulsifiable concentrate(EC) were greater than the critical surface tension of rice leaf, and the dynamic retention of the former on rice leaf was significantly greater than the latter. Pot experiment showed that under the same concentration, emamectionbenzoate ME showed an improved protecting effect on Chilo suppressalis compared to emamectionbenzoate EC. It testifies that micro emulsion could improve physical and chemical properties of the agents from the perspective of efficacy.

Key words: solution, surface tension, spreading, dynamic retention, insecticide efficacy trial

摘要： 研究了由05%甲维盐微乳剂配成的浓度为078~1250 mg/L药液在水稻叶上的表面张力特性及展布情况。结果表明,156~1250 mg/L甲维盐微乳剂药液的表面张力小于水稻叶临界表面张力。将005 mL药液点滴在水稻叶上的瞬间，不同浓度药液的接触角不同，但随时间的推移而变小，并且药液浓度越高接触角变小就越快，最终，药液中表面活性剂达到临界胶束浓度的药滴(312、625和1250 mg/L)在水稻叶上完全展布，而药液中表面活性剂没有达到临界胶束浓度的药滴(156 mg/L)则不能在水稻叶上完全展布。在相同的浓度下，156～100 mg/L的甲维盐微乳剂药液的表面张力小于水稻叶的临界表面张力，而甲维盐乳油药液的表面张力大于水稻叶的临界表面张力，并且前者在水稻叶面的滞留量明显多于后者。盆栽试验表明，相同浓度下微乳剂的保苗效果始于乳油，证明了微乳剂对药剂理化性能的改善。

关键词: 溶液, 表面张力, 展布, 滞留量, 药效试验