Infestation of wood poles by wood decay, copper-resistant fungi
Even in the age of internet telephony: still more than a million wood poles exist in Switzerland, of which half a million belong to Swisscom. They are affected by environmental influences, including the infestation of wood decay fungi.
Although the poles are impregnated with biocides such as copper, many fungi are now resistant to copper and convert copper into oxalic acid, which destroys the wood. In addition, the registration of impregnating materials such as chromium and boron will expire in the EU and Switzerland from 2019 onwards. Wood, tree and fungus researcher Prof. Dr. Francis Schwarze from Empa has found an antagonist against these wood decay fungi: Trichoderma harzianum. Special strains of Trichoderma harzianum keep the pathogen in control as antagonists. Furthermore, the natural wood protection by the biological active substance is environment-friendly.
As part of a joint research programme with MycoSolutions, Swisscom has been using the Avengelus G granules with Trichoderma harzianum as a preventive measure for every new pole that is set up or replaced since 2017. The granules are also applied proactively in the soil of affected masts. Medium- and long-term successes can only be tracked over time. However, our laboratory tests have shown that the wood protection agent Avengelus G is superior to other wood protection over a period of nine months. Wood treated with Trichoderma harzianum showed no damage even nine months after infection with pathogens, compared to the others treated with conventional alternatives. Thus, the service span of wood poles can be prolonged significantly thanks to biological control.
Further scientific evidence:
- Ribera, J., Fink, S., Bas, M.C., Schwarze, F.W.M.R. (2017) Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp. PLOS ONE. DOI pone.0174335.
- Ribera, J., Schubert, M., Fink, S., Cartabia, M., & Schwarze, F. W. M. R. (2017). Premature failure of utility poles in Switzerland and Germany related to wood decay basidiomycetes. Holzforschung, 71(3), 241-247.
- Ribera, J., Gandía, M., Marcos, J.F., Bas, M.C., Fink, S., Schwarze, F.W.M.R. (2017) Effect ofTrichoderma-enriched biochar in the integrated wood protection strategy. PLOS ONE.