Termite (Isoptera) damage and control in tropical forestry with special reference to Africa and Indo-Malaysia: a review

Abstract

AbstractTermite damage is a major problem in tropical forestry especially where exotic tree species are used. Stressed tress are generally the most susceptible to attack. Dry-wood termites (Kalotermitidae) live and feed in dead wood but sometimes attack living parts of mature trees; generally, they are pests only in the humid tropics, causing local but sometimes serious damage. Coptotermes (Rhinotermitidae) causes more widespread and serious damage to mature trees, especially in Malaysia and Australia. The most serious losses (up to 100%), due predominantly to various Macrotermitinae (Termitidae) such as Macrotermes, Odontotermes and Microtermes, occur in young, exotictrees such as Eucalyptus in dry regions in Africa and India. Chemical control of dry-wood termites is not feasible; use of resistant trees is probably the only satisfactory strategy. Control of Coptotermes by various methods has been suggested; but only insecticide injection into nests within affected trunks (Australia) and destruction of nests with explosives prior to planting, followed by destruction of queens in subsequently located nests (Papua New Guinea), are effective and economically viable. Attack on seedings, especially by Macrotermitinae in Africa and India, can be prevented by the increasingly unacceptable persistent cyclodienes used as mound poisons or as a barrier around the roots preventing attack by subterranean species. Controlled-release formulations of otherwise non-persistent insecticides are being development but are expensive and not widely available. Many non-chemical measures have been suggested, but none has been rigorously evaluated; none will provide the almost complete protection afforded by cyclodienes. Biological control shows little promise. Use of resistant tree species and development of resistant varieties offers the only long-term solution, but until these are available there will be a need to continue using cyclodienes or rapidly to develop alternative control methods.