C. trifolii may refer to: Coleophora trifolii, the trefoil thick-horned tinea or large clover case-bearer, a moth species found in Europe, North Africa, Asia Minor, Afghanistan and North America Colletotrichum trifolii, a fungal plant pathogen of alfalfa Curvularia trifolii, a plant pathogen Cymadothea trifolii, a fungal plant pathogen