Ginkgo snail-killing micro emulsion and preparation method thereof

The invention discloses a gingko snail killing microemulsion agent and a preparing method, which relates to the technical field of plant source agricultural drug production. The invention takes the seed shell extract of the gingko containing a ginkgoic acid as the source drug, and the invention is made by configuring auxiliary surface active agents, solution agent and antifreeze agent as well as water. The producing method comprises the following operating steps: the gingko external seed shell extract, the microemulsion agent and the solution agent are blended to be an even and transparent oil phase; the steamed water or the deionized water are added slowly to form an oil enclosed water type emulsion during the agitating process; through agitating and heating, the emulsion is rapidly converted into a water enclosed oil type; a steady O or W type emulsion after being cooled to reach the constant indoor temperature is obtained. The invention has fine environmental compatibility of the emulsion conformation, also completely realizes the advantages of the gingko snail killing agent with high efficiency to the snail and safety to people and animals. The microemulsion agent takes water as the main solvent with slight influence to environment. In addition, the invention has remarkable synergism; the LC 50 and LC 90 of the 24h respectively are 0.56mg per liter and 3.5mg per liter, which are obviously better than that of the 24h snail killing effect (LC50 is equal to 1.35mg per liter and the LC90 is equal to 3.85mg per liter) of the external seed shell extract of the original drug.