A blighted box?

What is box blight?
Box blight is a disease of box leaves and stems caused by two closely related fungi, Calonectria pseudonaviculata and Calonectria henricotiae (syn. Cylindrocladium buxicola). The two species of Calonectria differ in their sensitivity to some fungicides (triazoles). They largely affect Buxus spp. (box) in the UK, but other plants in the Buxaceae family are also susceptible.

Box blight is just one of a number of problems box suffers from. A second blight, called Volutella blight, also affects the plant, but is less serious. Box in the UK is also increasingly affected by box caterpillar.