Diethyl-pythiDC is primarily used in agriculture as a fungicide to control and prevent the spread of fungi and various plant diseases, especially in crops such as rice, soybeans, and orchard plants. It helps improve production efficiency and reduce damage from plant diseases. Additionally, it can be used as an ingredient in antifungal products in other industries, such as preserving wood and other materials against fungal degradation. Its application is carefully managed to ensure minimal impact on non-target species and the environment.