Intensity of dieback induced by Sphaeropsis sapinea in relation to site conditions

Following a hail storm in the southern Cape Province of South Africa, Sphaeropsis sapinea infected about 2000 ha of pine plantations. A series of sample plots yielded information on symptom development in relation to site factors and stand characteristics. Aerial photography and ground inspection of the area showed that, although the intensity of disease was not affected by site quality or age, it was inversely proportional to altitude.