Christchurch, New Zealand. PATHOLOGY OF TROPICAL HARDWOOD PLANTATIONS IN SOUTH-EAST ASIA*

Acacia mangium Willd., Eucalyptus spp., Tectona grandis L.f. (teak), Hevea brasiliensis (Willd. ex Adr. Juss.) Müll. Arg. (rubber), Paraserianthes falcataria (L.) I.C.Nielsen, and Gmelina arborea Roxb. (yemane) are the main tropical hardwood plantation species in South-east Asia. The occurrence of heart rot in acacias has received widespread attention but root rot is the most damaging disease of acacia plantations. Eucalypts face a different disease threat where outbreaks of leaf and shoot blights are most destructive. Teak, on the other hand, faces few disease threats although it has many insect pests. Since the 1980s, rubber has gained popularity as a source of timber (rubberwood or heveawood) and timber clones have recently been developed. The pathology of rubber is well understood and documented but the disease susceptibility of the new timber clones is currently unknown. In P. falcataria plantations gall rust appears to be an emerging threat. Yemane plantations in some parts of the world have failed due to disease problems, but no serious diseases threaten the South-east Asian plantations at present. Small plantations of other exotic and indigenous hardwood species have also been established throughout South-east Asia. Overall, comprehensive information on the pathology of many of the hardwood plantation species that have been planted in South-east Asia is lacking. Further co-operation, in particular from international agencies, needs to be continued and strengthened to ensure the success and continued productivity of hardwood plantations in South-east Asia for the betterment of local communities and economies