First Report of Asian Brown Rot Caused by Monilia polystroma on Apricot in Switzerland

A survey for Monilia fructicola (G. Winter) Honey on apricots (Prunus armeniaca L.) was conducted in July and August 2009 and 2010 in Canton Wallis, Switzerland. Mummies of fruits showing brown rot were collected and isolations were conducted. Nearly 200 fungal isolates, tentatively identified as M. fructigena, were retested with a multiplex PCR (1). With the Agilent 2100 Bioanalyzer (Agilent Technologies, Basel, Switzerland) instead of 1.5% agarose gels, the 23 bp difference between the diagnostic fragments of M. fructigena and M. polystroma van Leeuwen (1) could clearly be scored. M. polystroma was diagnosed in 3 of 65 and 1 of 132 isolates collected in 2009 (13 orchards) and 2010 (10 orchards), respectively. The internal transcribed spacer (ITS) regions of four isolates (09-G4, 09-P16, 09-S5, and 10-C6) were amplified and sequenced (4). The four sequences (GenBank No. JN128835) as well as those of the Hungarian isolate UFT (AM937114 [3]) were identical and highly similar to the type sequence for M. pol...