1. Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Veveří 97, 61142 Brno, Czech Republic, Department of Microbiology, Faculty of Medicine, Masaryk University Brno, Pekařská 53, 65691 Brno, Czech Republic, and State Phytosanitary Administration, Department of Diagnostics, Šlechtitelů 23, 77900 Olomouc, Czech Republic