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| PDF : |  16050213.pdf |
| title(En) : | On the Termite-resistance of Okinawan Timbers. I. Method of Bioassay and Effect of Wood Extractives on the Termite-resistance |
| author(En) : | Shiryo Yaga |
| information : | Mokuzai Gakkaishi 16(5), 213-218 (1970) |
| assort : | Original Article |
| summary(En) : | Each timber has a characteristic nature of termite-resistance. In the present paper, the relative values of antitermitic activities of various species of Okinawan woods against the subterranean termite, Coptotermes formosanus (SHIRAKI), were estimated. The following two methods were adopted to calculate the antitermitic values quantitatively. 1) Each test timber was exposed to 330 termites (300 workers and 30 soldiers) at room temperature and relative humidity of ca. 98%. After feeding for 40 days, the percentage of weight loss of timber due to the termite attack was determined. 2) The antitermitic values were also measured from the difference between initial and final weight of termites. Wood materials for the termite tests were prepared and examined in the forms of block, shaving, and meal respectively. The contribution of extractives was different among the wood species; especially those of Inumaki (Podocarpus macrophullus LAMB), Sugi (Cryptomeria japonica D. DON), and Sendan (Melia Azedarach LINN) were remarkable. |