Bartha, B., Mayer, A. and Lenz H.D. 2017. Acceleration of Ash Petiole Decomposition to Reduce Hymen-oscyphus fraxineus Apothecia Growth – a Feasible Method for the Deprivation of Fungal Substrate. Baltic Forestry 23(1): 82-88.

   A fungal pathogen, the ascomycete Hymenoscyphus fraxineus, is causing serious damages in the European common ash (Fraxinus excelsior) populations. Despite intensive investigations, there is currently no method to cure or slow down the ash dieback disease. A possible control strategy could be the treatment of the ash leaf litter to accelerate its decomposition and subsequently deprive the fungus of its substrate, thus preventing apothecia growth and its sporulation the next year. The aim of this study is to investigate the decomposition of ash petioles when covered with the leaf litter of different broad-leaved tree species (Tilia cordata, Carpinus betulus and Juglans nigra). Mass loss, physical fragmentation and lignin content of ash petioles were followed over a decomposition time of one year. Litter quality was determined based on their C, N and lignin contents and C/N and lignin/N ratios. Ash petioles covered with Tilia leaf litter had significantly higher fragmentation and decomposition rates af-ter a one year decomposition time compared to petioles without covering. Since all treatment plots had the same microclimatic conditions (temperature and relative humidity), the effect of higher fragmentation and decomposition was induced as a result of the chemical properties and quality of the covering litter type.

Keywords: Hymenoscyphus fraxineus, ash petiole, leaf litter decomposition, litter quality, disease control