冬青油微囊悬浮剂的制备及其杀蚜活性研究

以脲醛树脂为壁材,采用原位聚合法制备了20%冬青油微囊悬浮剂,同时研究了芯/壁材质量比、反应温度、搅拌速率、pH值及乳化分散剂等因素对微胶囊形成的影响,对所制备微胶囊的性能进行了表征,并测定了其缓释性能及其对菊小长管蚜Macrosiphoniella sanborni(Gillette)的田间防治效果。结果表明:当芯、壁材质量比为3:2、添加质量分数为3%的分散剂30%苯乙烯-马来酸酐共聚物(SMA)与Tween-80按质量比为1:1混合]酸酐共聚物(SMA)与Tween-80按质量比为1:1混合]、乳化搅拌速率为800 r/min、在120～150 min内将pH值调至2.0,在60～70 ℃下固化反应1 h时,可制备出形貌较好、平均粒径为7 μm左右的冬青油微胶囊。失重法测定结果表明,其缓释性能良好。田间试验结果表明,采用20%冬青油微囊悬浮剂在有效剂量300 g/hm2下进行常量喷雾处理,施药后第11天其对菊小长管蚜的防效仍维持在90%以上,具有较长的持效期。

Preparation of wintergreen oil capsule suspension and control efficacy on Macrosiphoniella sanborni

Wintergreen oil 200 g/kg capsule suspension(CS) was prepared using aphicidal wintergreen oil as core material and urea-formaldehyde as wall materials,and the preparation process was then optimized.In-situ polymerization was used to prepare the microcapsule.Experiments were performed to produce controlled-release microcapsules of wintergreen oil using a single factorial design.The independent variables were the weight ratio of core/shell material,agitation speed,pH,temperature and dispersant.The microcapsules were prepared with optimum properties under the following conditions:weight ratio of core/shell material at 3:2,3% mixture of SMA and tween 80 (1:1) as dispersant,agitation speed at 800 r/min,adjusting pH value to 2.0 within 120-150 min,and reaction 1 h at 60-70 ℃.The wintergreen oil 200 g/kg capsule suspension was applied to control Macrosiphoniella sanborni (Gillette) in the field at 300 g a.i/hm2,and the control efficacy was still higher than 90% after 11 days,indicating that 20% wintergreen oil capsule suspension is of long effective duration.