Abstract: 【Objective】 The objective of this study is to prepare acetochlor microcapsules by interfacial polymerization and highlight interrelation among these formulations, biological effect and environmental effect. 【Method】 The acetochlor microcapsules were prepared by interfacial polymerization method with styrene, butyl methacrylate, and diacetone acrylamide in the O/W emulsion. The performances of acetochlor microcapsules such as morphological structure, size distribution and chemical group were characterized by FESEM, DLS, IR and so on. Meanwhile, through study on the release performance of acetochlor microcapsules, the acetochlor residues in soil and the control efficacy on weeds, connection among the release mechanism, environmental behavior and control efficacy were investigated. 【Result】The prepared acetochlor microcapsules are spherical, the average particle size is 1.552 μm, the loading efficiency is 60%, and the content of acetochlor in formulation is 20%. Under laboratory conditions, when pH values kept at pH 7.0, the cumulative release rates of acetochlor were about 50% to 70% on the 5th day, 60% to 90% on the 10th day, and 80% to nearly 100% on the 30th day from 20℃ to 45℃. In the pH range of 5.0 to 9.0, the cumulative release rates of acetochlor were from 60% to 70% on the 5th day, from below 70% to nearly 80% on the 10th day, about 80% on the 30th day, and nearly 100% on the 40th day. The release of acetochlor microcapsules (MC) was accelerated with the increase of temperature and pH. The grassy weeds and total weeds control efficacy were 80.2%-95.4%, and 67.8%-82.1% on the 20th day, 82.2%-92.4%, and 70.2%-80.9% on the 40th day, and 87.0%-97.2%, and 62.6%-91.3% on the 60th day; fresh weight control efficacy were 90.1%-98.0% and 70.3%-88.7% on the 60th day. For the conventional acetochlor concentrated emulsion, the grassy weeds and total weeds control efficacy were 80.4%-90.2%, and 54.8%-76.1% on the 20th day, 83.0%-91.2%, and 61.4%-79.8% on the 40th day, and 81.1%-88.3%, and 71.2%-84.0% on the 60th day, respectively, and fresh weight control efficacy were 80.3%-83.4% and 65.9%-74.0% on the 60th day. Under field conditions, the amount of acetochlor in the soil gradually reduced over time, and the active ingredient amount of acetochlor microcapsules was higher than that of acetochlor emulsifiable concentrate (EC), which extended the control time and ensured acetochlor microcapsules a better control efficacy.【Conclusion】This delivery carrier may be extended to other lipophilic pesticide in the future. At the same time, more pesticide active ingredient for microcapsules than that of EC can improve the weeds control efficacy, and reduce the number of spraying and amount of pesticide for EC, and relieve the pressure on the environment.

Key words: acetochlor, microcapsules, soil residues, controlled release, control efficacy