Botanical acaricide and preparation method thereof

The invention discloses a botanical acaricide. The main ingredient of the botanical acaricide is elymus nutans extract. The elymus nutans botanical pesticide provided by the invention not only has obvious contact action on agricultural spider mites and does not cause pesticide resistance easily, but also is environmentally friendly, and is safe for non-target organisms such as human bodies and livestock. The elymus nutans is high in cold resistance and drought resistance, is wildly distributed in Tibet, Northwest, North and the like of China, is an important constituent part of grasslands and grassy marshlands, and becomes unique secondary metabolites in the long-term evolution process. At present, in high, cold and wet regions of China, abundant elymus nutans is cultivated and is mainly used for establishing artificial grasslands and pasturable grasslands, and resources are quite abundant. The preparation technology is simple and speedy, the mite killing effect is obvious, raw materials are low in cost and e