Although the surfactant itself has no biological activity, it can assist the solid or liquid active ingredients in pesticides to be quickly, uniformly and stably dispersed in the spray carrier, and ensure the distribution and attachment of the pesticide liquid on the surface of the organism (plant leaf surface and insect body surface). Surfactants also promote the absorption of the ingredients by the organism and can increase the conduction of the active ingredients in the organism, prolonging the residence time and improving the penetration of the plant epidermis, thereby enhancing the biological effect of the pesticide.
In addition, the type of surfactant and the ratio of the amount of surfactant added to the active ingredient will greatly affect the spray atomization and deposition of pesticides. Because the amount of surfactant can change the surface tension of the liquid, the surface tension of the liquid directly affects the contact angle of the leaf surface, which directly affects the distribution of pesticides on the plant surface, especially the leaf surface, and the droplets on the leaf surface.
As a surfactant for pesticides, it should have the following properties:
1) It has good emulsifying and dispersing properties. It requires less dosage and has strong adaptability to technical use, be resistant to acid and alkali, is not easy to be hydrolyzed, and can maintain a stable emulsion state under different water temperatures and water concentrations.
2) It has good chemical stability in contact with active ingredients, and should not decompose and fail due to a long period of storage. It does not increase the toxicity of the active ingredients to mammals and does not cause phytotoxicity to crops.
3) Abundant resources and low cost.
There are three types of surfactants, namely non-ionic, cationic, and anionic. Within non-ionic surfactant, sorbitan esters and polysorbates meet all the requirements of good pesticide surfactants. Sorbitan esters and polysorbates work effectively and depending on the formulation, they can combine with each other. Due to the characteristics of non-ionic surfactant, they are compatible with other surfactants, active and inert ingredients.