Diseases of plantation forestry trees in eastern and southern Africa

Plantation forestry is of growing importance in many countries of southern and eastern Africa. With the increased planting, the threat of pests and diseases to these new timber resources has also grown. The significance of pests and diseases to forestry plantations not only applies to the countries in which they are being set up, but also to neighbouring states where plantations are already established. Disease surveys have previously been conducted in East Africa, but mostly more than 20 years ago. We have undertaken a series of surveys in Kenya, Malawi, Mozambique, Tanzania and Zambia to obtain information on the present disease situation in eastern and southern Africa. Some diseases known from other areas of the world were identified and many of these represent new reports from the countries in which they have been found. The diseases encountered included cankers caused by species of Chrysoporthe, Botryosphaeria and Coniothyrium zuluense on Eucalyptus species; leaf and shoot diseases caused by species of Mycosphaerella and Cylindrocladium on Eucalyptus spp.; root rot caused by Armillaria spp. on Eucalyptus, Pinus and Acacia spp.; die-back and canker on Pinus spp. caused by Diplodia pinea and on Acacia mearnsii Phyrophthora root rot and wilt caused by Ceratocystis albifundus Some of these diseases can impart serious economic losses, so that forestry companies and organizations in East and southern Africa will need to re-vitalize or establish breeding and selection programmes to identify disease-tolerant planting stock. The preliminary surveys reported here provide a basis for the establishment of an effective African tree health network.