Panels of Lagerstroemia speciosa, Toona ciliata, Olea dioica, Pinus insignis, Acrocarpus fraxinifolius and Borassus flabellifer, pressure-treated with a 6.6% solution of Copper-Chrome-Arsenic (CCA) and 6% solution of Copper-Chrome-Boric (CCB), were exposed along with untreated controls, in triplicate, in Goa waters to, assess their resistance to damage by marine borers. The control panels were all completely destroyed within a short period of six months due to heavy infestation by borers, mainly Martesia striata (Linnaeus). Few specimens of Lyrodus pedicellatus (Quatrefages), Nausitora hedleyi Schepman, Bankia campanellata Moll and Roch, Bankia rochi Moll and Sphaeroma annandalei Stebbing were also noticed on some of the panels. Treated panels of Lagerstroemia speciosa and Toona ciliata indicated mild borer attack within six months and were heavily destroyed within 18 to 30 months. However, some panels of Pinus insignis and Borassus flabellifer, treated with CCA and CCB, and one of Olea dioica treated with CCA, were comparatively in good condition, with only mild attack even after exposure for 35 months. Two of these panels suffered just 15% damage at the end of 51 months. The results, in general, indicate that (I) biodeterioration of timber is quite severe in Goa waters beacuse of the predominance of Martesia striata; (II) CCB is almost as effective as CCA in some species upto about 35 months; (III) the same type of treatment or higher retention of preservative chemicals does not impart the same degree of protection to panels of different timber species; (IV) the effect of treatment with CCA and CCB varies in different timber species; and (V) treatment with solution of the same concentration does not ensure uniform absorption by panels of the same timber species.

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