Boxwood Blight Symptoms and Causes Boxwood Blight (also known as Cylindrocladium buxicola) is an aggressive fungal disease caused by the fungi Calonectria pseudonaviculata.  This disease strikes healthy Boxwood, quickly causing mass defoliation. You will typically see Boxwood Blight flair up during rainy or humid seasons, where the leaves stay wet for extended periods of time. If the fungi are present during ideal conditions, they will begin … Continue reading Boxwood Blight Verses Volutella Blight; Symptoms, Causes and Treatment