SDH-IN-27 (Compound Q18) is a succinate dehydrogenase inhibitor (SDHI) with an IC50 of 9.7 mg/L. It induces hyphal morphological changes and lipid peroxidation, demonstrating antifungal activity against C. camelliae with an EC50 of 6.0 mg/L. SDH-IN-27 also acts as an ergosterol biosynthesis inhibitor (EBI) by binding to the active site of CYP51, ultimately resulting in the death of pathogenic fungal cells.