Management of basidiomycete root- and stem-rot diseases in oil palm, rubber and tropical hardwood plantation crops

Basal stem-rot and root-rot diseases caused by basidiomycete fungal pathogens are naturally and widely occurring in a large range of hosts. However, they significantly reduce the productivity of several economically important plantation-crop industries in tropical countries. Oil palm, rubber, acacias and eucalypts are all susceptible to basidiomycete rot pathogens to varying degrees and there is no absolute disease resistance. The causal pathogens are persistent as they remain present in wood or crop debris even in the absence of living members of the host species. Disease build-up is often rapid and can reach economically unacceptable levels in the absence of interventions to contain the disease. This study reviews the biology and detection of root-rot disease in oil palm, rubber and hardwood crops with a specific focus on management strategies undertaken in South-East Asia. The diseases caused by basidiomycete rot pathogens in this region are intractable and require an integrated approach to disease management, as it is unlikely that any one control strategy will succeed. In contrast, there has been significant success in reducing losses from basidiomycete rot from pathogens in the northern hemisphere, especially with Heterobasidion annosum sensu lato in forest trees, research being often supported by the establishment of long-term trials required to understand the origins and types of disease. In the tropics, progress has been more fragmented due to the low level of research funding, the problems involved with managing long-term research trials in the tropics, the confidentiality requirements of competitive industries and the lack of literature available in the public arena. This review collates a large body of information from disparate and often obscure sources for oil palm, rubber, acacias and eucalypts, tropical plantation crops that face similar types of stem- and root-rot disease problems. Lessons to be learned from the successes and failures of various management strategies with each type of crop are examined.