Results on field stake tests against termite – Maximum for 8 years examination at Kumamoto in Japan
Various preservative treated or modified wood and charcoal painting stakes were tested in field, maximum for eight years in Kumamoto, distributed two main termite species, Coptotermes formosanus and Reticulitermes speratus. After two years in field, untreated sapwood of sugi (Cryptomeria japonica) were observed severe attacks by termites, but the preservative treated stakes were observed no significant attacks by termites. After eight years experiment, treated stakes with preservatives not included copper, like DDAC and zinc-naphthenate, were observed slight or moderate attacks by termites. Otherwise, in the case of treated stakes with preservatives included copper, like ACQ, copper naphthenate and Tanalith CuAz, no significant attacks by termites were observed. Few samples of chemically modified wood or LVL were observed slight attacks by termites for seven years.
Keywords: Termite, Field test, Preservative treated wood, Chemically modified wood, Charcoal based paint