助剂对10%苯醚甲环唑水分散粒剂在荔枝叶片表面润湿性能的影响
Effects on wettability of 10% difenoconazole water dispersible granule with adjuvants on litchi leaves

采用接触角测量仪测定了10%苯醚甲环唑水分散粒剂（difenoconazole WG）不同倍数稀释液在荔枝叶片上的静态接触角和0～60 s动态接触角，用于计算荔枝叶片的临界表面张力和表面自由能，进而分析药液在荔枝叶片表面的润湿性能；采用全自动张力仪测定了在10%苯醚甲环唑WG不同稀释液中分别添加体积分数为0.4%的silwet stik和0.2%的as 100 2种助剂后溶液的表面张力，研究了助剂添加前后表面张力的变化。结果表明：荔枝叶片近轴面的表面自由能为23.74 mJ/m2，远轴面的表面自由能为11.89 mJ/m2，均以色散力分量（非极性分量）为主导。在10%苯醚甲环唑WG 500倍稀释液中加入体积分数为0.4%的silwet stik溶液，其表面张力为21.90 mN/m，低于荔枝叶片的临界表面张力（22.64 mN/m），且在0～10 s内接触角下降最快。研究结果表明：荔枝叶片的近轴面比远轴面更易被药液润湿；在荔枝园喷施10%苯醚甲环唑WG时，若在稀释倍数500倍的药液中添加0.4%的silwet stik助剂，则可使药液在叶片上能更快更好的润湿铺展。
The critical surface tension (CST) of litchi leaf, as well as the surface free energy (SFE), surface tension, static contact angle and dynamic contact angle in 0-60 s of diluted solution of 10% difenoconazole water dispersible granule (WG) were determined by using contact angle measuring device and automatic surface tension meter. Effects on wettability of difenoconazole WG with adjuvants (0.4% silwet stik and 0.2% as 100) on litchi leaf surface were also investigated．The results showed that the SFE value of the adaxial surface of litchi leaf was about 23.74 mJ/m2, while the SFE value of the abaxial surface was about 11.89 mJ/m2，and the dispersion component was dominant．The surface tension of 500-fold dilution of 10% difenoconazole WG with 0.4% silwet stik on litchi leaf was 21.90 mN/m, while the CST of lichi leaf was 22.64 mN/m. The contact angle of WG’s 500-fold dilution with silwet stik declined the fastest during 0-10 s．The results suggested that the adaxial surface of litchi leaf was more wettable than the abaxial surface. When 10% difenoconazole WG was applied to lichi trees，the best performance was accheived by 500-fold dilution with 0.4% silwet stik adjuvant．