1. Wageningen UR–Plant Research International, 6700 AB Wageningen, The Netherlands
2. Foundation Kompetenzzentrum Obstbau-Bodensee, 88213 Ravensburg-Bavendorf, Germany
3. University of Debrecen, Centre for Agricultural Sciences and Engineering, Faculty of Agronomy, H-4015 Debrecen, Hungary, and Plant Protection Institute, Hungarian Academy of Sciences, 1525 Budapest, Hungary
4. Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland
5. Wageningen UR–Plant Research International, The Netherlands.