This study investigates the uptake, translocation, and pathogen control efficacy of ethylicin in tomato plants using a combination of indoor root irrigation, spraying, and field root irrigation experiments. The results indicate that ethylicin shows dual-directional translocation in tomato plants. On the third day after foliar spraying, ethylicin was detected in the roots at a concentration of 2.93 mg/kg, indicating downward movement. On the third day after root irrigation, ethylicin was detected in the leaves at a concentration of 3.44 mg/kg, confirming upward movement. In the field experiments, ethylicin was absorbed and transported to the upper leaves within six hours of root irrigation at a concentration of 3.85 mg/kg for a single-agent ethylicin and 5.87 mg/kg for an ethylicin–oligosaccharin compound. These results indicate that oligosaccharins enhance the absorption of ethylicin. Ethylicin residue dissipated by the fifth day. No ethylicin was detected in the untreated controls. Root irrigation during the growing period showed an effective reduction of Fusarium spp. and Phytophthora spp. populations in the soil and control of soil-borne diseases. These findings provide theoretical support for the efficient application of ethylicin in the field.