The toxicity of tributyltin oxide to the wood‐boring beetles Lyctus brunneus Steph. and Anobium punctatum (Deg.)

SUMMARY When tributyltin oxide (TBTO) was tested by British Standard 3653 against Lyctus brunneus, 0·5 % solution, equivalent to 0·72 g/m2 surface application, gave almost complete protection. Tests to BS 3651, using larvae of Anobium punctatum transferred into fully impregnated wood gave toxic limits of 1·39–2·93 kg/m3 TBTO when benzene was used as diluent. The use of white spirit as diluent gave lower toxic limits, probably due to combined toxic action of TBTO and white spirit residues. TBTO appears to have no contact action against the insects tested. Probit analysis of the test with A. punctatum gave an LD 50 of 0·254 kg/m3 and an LD99 of 3 kg/m3. The advantage of treating results by probit analysis rather than by deriving ‘toxic limits’ is discussed.