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Root rot disease of teak (Tectona grandis Linn. f.) is widely distributed in Nigeria where it is present in about 70% of teak plantations. The disease is caused by Rigidoporus lignosus (Klotzsch) Imazeki, sporocarps of which have been found in about 64% of the infected plantations. Disease incidence is more serious in shallow lateritic soils and sites with impeded drainage. The disease can be controlled using 2% Tillex chemical spray on infected trees. It can also be largely reduced in proposed plantations by careful site selection and pre-treatment of stumps left behind after land clearing.

Sodium pentachlorophenol, which was previously found to be the most effective of eight different chemicals tested against blue-stain of timber and recommended at 1 and 2% levels for dipping, has now been further tested in the field. The results show that the chemical effectively controlled the blue-stain infection even at lower concentrations of 0.5 and 0.7%. Botryodiplodia theobromae was the chief causal agent of infection, although a Ceratocystis sp. was also present. The chemical at the concentrations used had a repelling action for 4-6 days after application on insect borers (Platypus hintzi and Xyleborus performa).