Chemical control of blue stain and insect boreres in Pterygota macrocarpa logs at a Ghanaian logging site

Abstract

Pterygota macrocarpa has emerged as a very popular timber species for the manufacture of plywood in Ghana. However, the blue stain fungus, Lasiodiplodia theobromae moulds and insect borers cause serious damage to the timber between the time of felling and extraction. This study assessed the potential of some chemical preservatives to reduce the impact of blue stain and insect borers on P. macrocarpa logs and determined the best treatment period for short-term preservation of the timber. Logs were treated with (i) fungicides (Antiblue and Bumper) (ii) an insecticide (Pyrinex) (iii) a combination of a fungicide and an insecticide and (iv) Kerosene. Experiments were conducted during both dry and wet seasons and included controls (no treatment). Treatments with combinations of Antiblue and Pyrinex soon after felling prevented sapstain and mould growth during the first fourteen days in the dry season but traces of sapstain appeared after seven days in the wet season. All preservatives showed at least 95% effectiveness in controlling stain in both dry and wet seasons when treatments were carried out immediately after felling but dropped to below 80% after seven days exposure in the wet season. The best chemical treatment for the suppression of insect borers was combinations of Pyrinex and Bumper and Pyrinex and Antiblue for dry and wet seasons, respectively.

Keywords: Pterygota macrocarpa, chemical preservatives, sapstain, logs

Ghana Journal of Forestry Vol. 17 & 18 2005: pp. 56-70