Natural bioresistance of eighty-two species of Indian timbers to attack by marine wood-borers has been presented based on data collected from test panels exposed in Goa waters (west coast of India) for periods ranging from five to thirteen months. All the timber species, except Artocarpus gomeziana and Pterocarpus santalinus, were completely destroyed within a short period of three to six months. Panels of Artocarpus gomeziana and Pterocarpus santalinus, however, suffered only 50% and 40% average internal destruction in 9 and 13 months respectively. Destruction was mainly due to severe infestation by Martesia striata, Nausitora hedleyi, Lyrodus pedicellatus and Bankia rochi. The results have been compared and discussed with those reported by previous workers. Factors, such as chemical inclusions and specific gravity of timber, types of borers dominant at the test site, intensity of fouling settlement etc., which impart and/or influence natural durability of various timbers under marine conditions, have been briefly dealt with so as to explain the discrepancy of results obtained by different investigators and also the reported inter-site and intra-site variations observed in several instances.

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