1. Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
2. Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA
3. Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE, Université d’Orléans, F-45067 Orléans, France
4. Institute for Sustainable Plant Protection-National Research Council (IPSP-CNR), 50019 Sesto Fiorentino, Italy