Development of QoI resistant alleles in populations of Ramularia collo-cygni

Abstract

Summary Ramularia collo-cygni first appeared as a major pathogen of barley in Scotland during 1998 and was found to be easily controlled by the fungicide azoxystrobin (Amistar). This type of fungicide was therefore recommended for Ramularia leaf spot disease control. However, during 2002 there was a sharp decline in the efficacy of azoxystrobin, when used to control Ramularia leaf spot. It was therefore assumed that fungicide resistance had developed, although it was not confirmed by either bioassay or sequencing. This study showed that mutations causing QoI fungicide resistance were present in almost all recently obtained R. collo-cygni isolates from across Europe.