Can we predict Sphaeropsis sapinea outbreak by monitoring fungal diversity in austrian pine plantations?

Abstract

Fungal diversity plays an important role in forest ecosystems stability as well in the health status of mycorrhizal forest trees. At research area in Istria, Croatia, pathogenic fungus Sphaeropsis tip blight (Sphaeropsis sapinea (Fr.) Dyko et Sutton) caused substantial damage in Austrian pine (Pinus nigra J. F. Arnold) plantations during the last decades. This research continues on previous done in Austrian pine plantations on predisposition to S. sapinea infections, where site and stress conditions were determined as key factors, but also, the ectomycorrhizal (ECM) fungi were confirmed as biological indicators of the health status in selected plantations. We analyzed fungal diversity of Austrian pine plantations to determine the dependence of species richness and its diversity index, both for total and ECM species only, in relation to S. sapinea infection rate and crown transparency of selected trees. Fungal samples were collected during 2013 at nine permanent research plots in autumn season. Their total and ECM species richness and diversity index were correlated to Sphaeropsis tip blight infection level and crown transparency. Our results did not confirm the hypothesis that Austrian pine plantations with higher total species richness and its diversity index are more resistant to S. sapinea infection nor to crown transparency. Oppositely, ectomycorrhizal species richness and its diversity index might be used as good biological indicators of S. sapinea presence and crown transparency of studied plantations.