作物叶片表面自由能及喷雾助剂对农药药液在5种作物叶片上润湿性能的影响

为了解不同作物叶片表面润湿性能，科学选用助剂提高化学防治水平，采用光学视频接触角测量仪分别测定了小麦、玉米、辣椒、大豆和苹果5种作物叶片的表面自由能及其分量，进一步测定了2%甲氨基阿维菌素苯甲酸盐微乳剂和20%阿维·杀虫单微乳剂两种药液液滴在添加Silwet 408和GY-Spry两种喷雾助剂后其在5种作物叶片上的接触角。结果表明：5种作物叶片正反面表面自由能差异较大，表面自由能最大和最小的分别为辣椒叶片(54.12、45.08 mJ/m2)和小麦叶片(3.76、6.42 mJ/m2)；同种作物叶片正反面表面自由能均有差异，其中辣椒叶片正反面和大豆叶片正面自由能以极性分量占主导，表现出亲水性，小麦、玉米、苹果叶片正反面及大豆叶片反面自由能以色散分量占主导，表现出疏水性。在2%甲氨基阿维菌素苯甲酸盐微乳剂5 000倍液和20%阿维·杀虫单微乳剂750倍液中分别添加两种助剂后，药液液滴在5种作物叶片上的接触角均有不同程度降低，其中添加Silwet 408后两种药液接触角分别降低82.63%～100%和85.07%～100%，添加GY-Spry后分别降低0～57.54%和10.96%～59....

Effects of surface free energy of crops leaves and spry adjuvants on the wettability of pesticide solution on five crop leaves

In order to understand the surface wettability of leaves of different crops and improve the efficiency of chemical control by the scientific selection of adjuvants, the surface free energy and its components of wheat, corn, pepper, soybean, and apple leaves were measured by optical video contact angle measuring instrument. The contact angles of 2% femamectin benzoate ME and 20% abamectin + monosultap ME on the leaves of the above five crops were measured. The results showed that there were great differences in the adaxial and abaxial surface free energy of five crop leaves. The maximum and minimum surface free energy were pepper leaves (54.12 and 45.08 mJ/m2) and wheat leaves (3.76 and 6.42 mJ/m2), respectively. There were differences in surface free energy of the adaxial and abaxial leaves of the same crop. The adaxial and abaxial free energy of pepper leaves and the adaxial free energy of soybean leaves are dominated by polarity component, manifesting hydrophilicity, while the adaxial and abaxial free energy of wheat, corn, apple, and the abaxial free energy of soybean leaves are dominated by dispersion component, manifesting hydrophobicity. When Silwet 408 and GY-Spry were added to the 5000-fold solution of 2% femamectin benzoate ME and 750-fold solution of 20% abamectin + monosultap ME, the contact angle of the solution on the leaves of five crops decreased to varying levels. After adding Silwet 408, the contact angles of the two solutions decreased by 82.63%-100% and 85.07%-100% respectively. With the addition of GY-Spry, they decreased by 0-57.54% and 10.96%-59.13% respectively. The addition of Silwet 408 decreased the contact angle more significantly than GY-Spry. The decreasing trend of contact angle of the two insecticides added with adjuvants on the leaf surface of five crops was the same, and the decreasing trend of contact angle in 0-30 s was significantly higher than that in 30-60 s. Both Silwet 408 and GY-Spry improve the wettability of 2% femamectin benzoate ME and 20% abamectin + monosultap ME to five targets, and Silwet 408 is superior to GY-Spry.