Sphaeropsis sapinea, with Special Reference to its Occurrence onPinusSpp. in South Africa

SYNOPSIS Sphaeropsis sapinea (=Diplodia pinea) causes shoot blight, canker, collar rot, root disease and blue stain of Pinus spp. In South Africa, it has restricted the cultivation of Pinus radiata almost entirely to the South-Western Cape. It is also important on Pinus patula growing in the summer rainfall areas. Favourable conditions for infection are wet weather and high temperatures (25°C optimum) coinciding with new shoot growth. Hail and other injuries, and stress conditions (especially moisture stress) are important factors predisposing trees to infection. Control measures include sanitation, forest management practices to reduce stress and injury to trees, and the use of both inter and intra-specific host resistance. Fungicidal control is practical only in nurseries. Some research priorities are given.