Wood decay performance of strobilurins preservatives

  Objective  Wood preservative treatment is an effective way to prolong the lifespan of wood, reduce deforestation and further improve the ecological environment. In this study, in order to provide a basis for the development of eco-friendly wood preservatives and enrich the wood preservative system, the decay performance of a series of methoxyacrylate fungicides, iodopropynyl butyl carbamate (IPBC) and 4, 5-dichloro-N-octyl-4-isothiazolin-3-one (DCOIT) has been systematically screened.

  Method  In order to discover novel agents with high-activity to control wood rot fungus, the inhibition zone method was used to test the antifungal activity of 5 candidate agents (azoxystrobin, kresoxim-methyl, pyraclostrobin, IPBC and DCOIT) against wood rot fungus. Then the high-activity agents were prepared into water-based formulations, and the method for lab sand block test was used to evaluate interior decay resistance of treated materials at different levels of drug retention.

  Result  The inhibition zone results indicated that azoxystrobin, pyraclostrobin, DCOIT and IPBC showed good inhibitory effects on brown rot fungi and white rot fungi. Especially, pyraclostrobin and IPBC exhibited high antibacterial effects, which were higher than the control agent propiconazole. For the preservative treated radiata pine material under the chemical retention of about 0.21−0.46 kg/m³, the mass loss rates of treatment material by azoxystrobin and pyraclostrobin for white rot fungi and brown rot fungi were 3.1%−7.9% and 3.5%−7.8%, respectively. Moreover, the mass loss rate of IPBC treatment radiata pine material was 0.9%−5.6% under the chemical retention of about 0.2 kg/m³. The lab sand block test of the preservative treated Populus tomentosa results showed that the decay resistance of all the treated samples at different chemical retention levels was much better than that of the untreated samples. However, their mass loss rate was still large. It is not recommended to use this kind of fungicides for the preservative treatment of Populus tomentosa.

  Conclusion  In this study, the antifungal activity of pyraclostrobin and azoxystrobin formulations is equivalent to the control agent propiconazole, and antifungal effect of IPBC is better than propiconazole. So they could be further developed and utilized as a novel wood preservative.