The effect of preservative distribution in small blocks of Pinus sylvestris on the toxicity of tributyltin oxide to Reticulitermes santonensis Feytaud
M P Levi, D N R Smith
Small blocks of Pinus sylvestris (50x25x15 mm³) were treated by a full-cell method with various concentrations of tributyltin oxide in benzene. Replicate blocks were then freeze dried, rapidly air dried or slowly air dried and exposed to surface attack by the subterranean moistwood termite Reticulitermes santonensis Feytaud. At all concentrations it was found that the freeze-dried blocks were more heavily attacked than the air-dried ones, and that a threshold value determined in the normal way using air-dried blocks could be much underestimated. This agrees with what one would expect from the uneven distribution of preservative produced by air drying compared with the uniform distribution obtained by freeze drying. The results with slow air drying were in between those obtained from the other two methods. Further work is required to check the value of this method.