EFFECTIVENESS OF A ORGANIC IODINE COMPOUND AGAINST WOOD DECAYING FUNGI AND TERMITES

Abstract

The effectiveness of a low toxicity organic compound as fungicide and insecticide was studied by a accelerated laboratory bioassay according to the japanese standard. The compound was evaluated at concentrations of 0,5, 0,75 and 1,0% using ethanol as solvent. The subterraneous termites Coptotermes formosanus Shiraki and the decay fungi Coriolus versicolor (white rot) and Tyromyces palustris (brown rot) were used in the trials to evaluate the insecticide and fungicide action respectively. The wood specimens with dimensions of 40 x 20 x 5mm were treated by surface coating (brushing) method at a rate of 110±10g/m². The percentage weight loss of the wood blocks and the termite mortality (insecticide action) and the weight loss of the wood blocks before and after the fungi attack (fungicide action) were determined. The efficiency of the formulations were evaluated according to the Value of Efficiency. Results showed that the compound was of little or no efficient as insecticide against Coptotermes formosanus in the three concentrations analysed. The compound showed a good performance as fungicide against Coriolus versicolor and Tyromyces palustris with a Value of Efficiency higher than 90 in the three concentrations analysed. The best results were obtained with the product at 1,0% concentration in the treated and unleached wood specimens. Tyromyces palustris caused a larger damage in the wood blocks than Coriolus versicolor. The product showed a low capacity of fixation in the wood; therefore, it is not indicated for treating wood that will be in direct contact with the soil or under outdoor conditions.