Mixed fatty acids are antiviral inducers, milky yellow liquid, and the main active ingredients are mixtures of C13~C1S fatty acids. It has the dual effect of inducing plant disease resistance and stimulating crop growth. It has hormone activity to plant itself and has passivation effect to virus, and can effectively inhibit the proliferation and expansion rate of virus in plant. It can induce the advance expression of crop disease resistance genes, help to improve the content of disease-resistance related protease, make susceptible varieties reach or approach the resistance level of resistant varieties, have obvious prevention and control effect on crop virus disease, and can effectively prevent and control virus disease of fruit trees, cash crops, vegetables, flowers, tobacco. The product can effectively increase the content of unsaturated fatty acids in membrane lipid, thus greatly improving the cold resistance of plants. It is a low toxic pesticide, safe for human and livestock. The main dosage forms are 10% water emulsion and 10% water agent