Observations of Termite-Fungus Interactions of Potential Significance to Wood Biodeterioration and Protection

1. Diversity of Malaysian termite fauna and mycoflora - a threat to timbers

The food of termites is essentially cellulosic materials. Degradation of wood by termites is a chronic problem in many tropical and even some temperate regions of the world, resulting in serious monetary and material losses with far reaching impact on the increasing demand for timber. In Peninsular Malaysia, the termite fauna is diverse, represented by three families, comprising a total of 175 species from 42 genera (Tho 1992), among which the subterranean termite Coptotermes appears to be the most prevalent genus foraging around buildings and in houses (Rath & Tidbury 1996, Tho & Kirton 1990), infesting also forest plantation living trees (Kirton et al. 1999). Additionally, termites of the genera Schedorhinotermes, Globitermites, Odontotermes, Macrotermes and Microtermes, are also reported as important pests in agricultural crops (Rath & Tidbury 1996), trees, logs, timbers and other cellulosic materials. There are far fewer Malaysian timber species nowadays with proven termite resistance (Grace et al. 1998, Wong et al. 1998), implicating that the vast remaining termite susceptible Malaysian woods would require some treatment to enhance their service life.

The humid tropics of Malaysia is also favourable for growth and development of decay fungi, where both white rot (Basidiomycetes) and soft rot (Ascomycetes and Deuteromycetes) decay are the most common types of fungal attack of Malaysian timbers (Wong & Pearce 1997, 1998). Studies have shown that many Malaysian timber species are susceptible to soft rot decay (Wong & Pearce 1998, Wong & Peek 1997). Another group, the sap-stain and mould fungi (loosely called the non-decay fungi) causes serious discoloration (Wong etal. 1999) of fresh-felled sapwood limbers without affecting the wood structure. It is well observed that termites are associated with fungi as joint colonisers and degraders of wood material (wood biodcterioration), while instances of fungal attack or termite infestation of wood materials occurring singly or the same structure are also observed. Hence observations of both positive (synergistic) and negative (antagonistic) interactions between the two groups of tropical degraders suggest a potential for tapping this information to develop strategies for wood protection and termite control in plantations and buildings.