If you are growing wheat or barley you will be familiar with names like Septoria leaf spot, scald, powdery mildew, rust and maybe tan spot. Within New Zealand we are fortunate that wheat and barley are only attacked by a handful of important diseases. While there are additional diseases, they tend to be relatively uncommon and often only have a minor impact on crop yield. This means it is feasible to identify them all with a good degree of certainty.