TAXONOMY AND IDENTIFICATION OF SEPTORIA AND STAGONOSPORA SPECIES ON SMALL-GRAIN CEREALS.

Numerous significant changes have been made in the taxonomy of both the anamorphs and teleomorphs of the Septoria group of leaf spot pathogens on small grain cereals during the past 30 years. The pathogens fall into two related but distinct groups, with anamorphic genera now placed in Septoria and Stagonospora of the Sphaeropsidales. Each of these genera has distinct teleomorphs in the Loculoascomycetes in Mycosphaerella and Phaeosphaeria. These reclassifications were based largely on fungal morphology and host pathogenicity as originally characterized. Recent studies have investigated the phylogenetic relationships among these species using the techniques of molecular genetics, and have related molecular characteristics to taxonomy based on classical morphology. A clearer understanding of the taxonomy of this group will enhance our ability to diagnose and manage these important cereal pathogens.