Blocks of sapwood of Pinus nigra were treated by vacuum impregnation with Biocide A to retentions of 0.5, 1 and 2 kg m-3. Similar blocks were vacuum-pressure impregnated with CCA to retentions of 2, 24 and 38kg m-3. The blocks were exposed subtidally in Mourilyan Harbour (Queensland, Australia). After 5 and 10 months exposure, blocks were removed, examined for superficial signs of attack by wood borers and X-rayed to reveal any teredinid tunnels. Higher retentions of both types of preservative prevented borer attack over the first 5-month period. After 10 months, all 3 loadings of Biocide A-treated samples had been moderately attacked by teredinids. Control blocks were heavily attacked with up to 0.23 ± 0.09 borers cm-2 after 5 months and 0.42 ± 0.07 borers cm-2 after 10 months. Slivers of wood from other blocks treated to the same preservative retentions were subjected to 6 days of leaching in running seawater. Individual Limnoria lignorum were placed, with a wood sliver in 6 ml of seawater in the cells of a repli-dish. The repli-dishes were maintained at 17°C and water was changed every 3 days. Faecal pellet production was monitored over a 1-week period. Pellet production was highest on untreated wood and lowest at the 2kg m-3 loading of Biocide A -treated wood. L.lignorum in contact with these shavings were less active and became covered with debris, whereas those in contact with CCA-treated wood and untreated wood continued to be active and remained free from debris.

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