The effects of subthreshold loadings of tebuconazole, DDAC, and boric acid on wood decay by Postia placenta
AbstractTebuconazole, didecyldimethylammonium chloride (DDAC), and boric acid are co-biocides frequently added to copper-based wood preservative systems. Although the performance thresholds of these biocides are well known, there is currently little information on the effects of subthreshold loadings of the co-biocides on common wood decay fungi. We tested five strains ofPostia placentaon white pine cubes (Pinus strobus) treated with subthreshold retentions of tebuconazole, DDAC, or boric acid. No stimulatory effects were observed on blocks treated with DDAC or boric acid. Decay stimulation, as measured by weight loss, occurred between loadings of 1.0×10-5to 1.0×10-3 kg m-3on blocks treated with tebuconazole. This effect should be taken into account during the design and use of wood preservative systems containing this fungicide.