Biodeterioration of treated Pinus radiata timber by Australian decay fungi and the termite Coptotermes acinaciformis in laboratory bioassays and field conditions

Abstract

Abstract The resistance of Pinus radiata sapwood blocks treated with a boron-based preservative to biodeterioration by five Australian wood destroying fungi [Fomitopsis lilacino-gilva, Coniophora olivacea, Gloeophyllum abietinum (boron resistant), Serpula lacrymans and Perenniporia tephropora] was investigated. A phenyl pyrazole termiticide (fipronil) was also incorporated into the formulation to determine whether its presence affects biological efficacy. A linseed oil, liquid wax, terebene and trimethyl borate formulation inhibited decay by the trial fungi. Incorporation of fipronil did not affect the fungicidal properties. Fipronil alone exhibited no fungicidal activity. The termiticidal activity of fipronil was assessed (termite field test) in a formulation incorporating a fungicide, water repellent and drying agent in an alternative solvent carrier to that previously reported. The biological activity of the test compound was not diminished in this system. The 1-year progress performance of an ongoing in ground graveyard trial of similarly treated stakes, exposed to numerous termite species and decay fungi in tropical field conditions, is also presented. The predominant biological agent at the field site is the Australian subterranean termite Coptotermes acinaciformis (Froggatt). Treated stake samples of the Australian softwood Pinus radiata were exposed.