Septoria leaf blotch of wheat: sensitivity to fungicides of the Swiss Mycosphaerella graminicola population

The fungicide resistance level of M. graminicola, a major agent of leaf blotch of wheat, was evaluated in 2008 for samples from 17 fields. Genes coding for the target proteins of QoI and DMI fungicides were characterised genetically. The frequency of the mutation conferring QoI resistance ranged between 1 and 96%, indicating that the Swiss M. graminicola population is in a transitory phase. Compared to other European populations of this pathogen, the Swiss population is on average more sensitive to DMI fungicides. These results represent the basic information to formulate recommendations regarding the use of these two fungicide groups to achieve a durable chemical control of this widespread leaf disease of wheat.