Abstract:

Objective: In order to evaluate the durability of wood treated by cyproconazole (Cy), cupraamine/ammonia/Cy (CuCy) and epoxiconazole (EPO) formulations, the suitable retention of the above formulations for exterior ground contact circumstance (C4.1) was determined for national standard and its practical application. Method: The water soluble micro-emulsions of Cy as well as EPO were prepared and impregnated into masson pine and radiata pine through vacuum pressure process. According to the national standard《Method of evaluating wood preservatives by field tests with stakes》(GB/T 27655—2011), the decay and termite resistance index of cyproconazole, CuCy and epoxiconazole treated masson pine and radiata pine was calculated and the natural durability was conducted and determined. Result: At Beijing field test site, located in medium biological hazard zone (Z2), the decay resistance index of all Cy and EPO treated wood with retention above 0.049 kg·m^?3 was above 9.0 after 7 years. The decay resistance index of all CuCy treated pines was 10 after 11 years, while the retention was 1.60-3.20 kg·m^?3 for masson pine, and the retention was 1.40-3.04 kg·m^?3 for the radiata pine. The decay resistance of CuCy treated wood was excellent and was equivalent to that of cupraamine/ammonia/tebuconazole/propiconazole (CuPT) treated wood with the same retention at Beijing test site. For all the masson pine treated by CuCy at Guangzhou test site, located in severe biological hazard zone (Z4), the decay resistance index was above 9.78 at the retention 1.97-2.80 kg·m^?3, and the termite resistance index was 7.15 at the retention of 2.80 kg·m^?3 after 11 years. Conclusion: The results showed that the CuCy treated wood with retention above 1.60 kg·m^?3 performed excellent protection for decay under the usage C4.1 in Z2, while CuCy treated wood with retention above 2.80 kg·m^?3 performed good protection for both decay and termite in Z4. The decay resistance of Cy and EPO treated wood was more efficient than that of tebuconazole and propiconazole in Z2, while the durability of wood treated by CuCy was equivalent to that treated by CuPT at the same retention in both Z2 and Z4.

Key words: cyproconazole, epoxiconazole, copper triazole, field stake test, durability