The efficacy of six triazole fungicides was compared using a fungus cellar soil bed test, a rapid antisapstain laboratory trial and a 36 week antisapstain field trial. After 21 months in the fungus cellar the mean soundness of radiata pine treated with 1.5 kg/m³ of cyproconazole, azaconazole, hexaconazole, tebuconazole, propiconazole and flusilazole in combination with 1.0 kg/m³ didecydimethyl ammonium chloride was 18, 34, 37, 72, 80 and 80% respectively. Wood treated with 4.7 kg/m³ of CCA salt and 2.1 kg/m³ tributyltin oxide had mean soundness values of 62 and 73%. Antisapstain trials showed that of the triazoles tested hexaconazole and cyproconazole gave the best protection and at a concentration of 0.05% w/w, in combination with 0.04% w/w carbendazim and 0.5% w/w DDAC, 92% of boards had less than 5% surface degrade after 24 weeks (March-August). It was clear from the results that the spectrum of fungicidal activity of a given triazole varied considerably. For example tebuconazole performed relatively poorly against hyphomycete moulds and sapstain fungi such as Ceratocystis piceae on green timber but in a fungus cellar soil bed at a retention of 0.5 kg/m³ gave equivalent protection to 4.7 kg/m³ of CCA salt (NZTPC above ground specification) and 2.1 kg/m³ tributyltin oxide (2.5 times conc. in NZTPC spec.). Hexaconazole gave the best performance as an antisapstain but performed relatively poorly in the fungus cellar.

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