Stagonospora nodorum

Stagonospora nodorum is a fungal pathogen that causes Stagonospora nodorum blotch (SNB), a disease that affects wheat and other cereal crops. It is a member of the Ascomycota phylum, which includes a wide range of important plant pathogens.

Taxonomy

The fungus was first described in 1890 by German mycologist Heinrich Friedrich Link, who named it Septoria nodorum. It was later reclassified in the genus Stagonospora by Dutch mycologist Johannes Müller Argoviensis in 1892. The current accepted name is Stagonospora nodorum (Berk.) Castell. & Germano.

Life Cycle

The life cycle of Stagonospora nodorum involves both sexual and asexual reproduction. The fungus overwinters as mycelium or pseudothecia in crop residues. In the spring, it produces ascospores which are dispersed by wind and rain to infect new plants. The fungus can also produce asexual spores called conidia, which can cause secondary infections throughout the growing season.

Disease Symptoms

The primary symptom of SNB is the formation of dark brown to black lesions on the leaves, stems, and glumes of infected plants. These lesions often have a yellow halo, and can coalesce to cover large areas of the leaf surface. In severe cases, the disease can cause significant yield loss.

Management

Management of SNB involves a combination of cultural practices, such as crop rotation and residue management, and the use of resistant wheat varieties. Fungicides can also be used, but their effectiveness can be limited by the development of fungicide resistance in the pathogen population.

Economic Impact

SNB is a major disease of wheat in many parts of the world, including North America, Europe, and Australia. It can cause significant yield losses, particularly in years with wet spring weather. The economic impact of the disease is further increased by the cost of fungicide applications and the need for resistant wheat varieties.

Research

Research on Stagonospora nodorum is focused on understanding the genetic basis of pathogenicity and host resistance, with the aim of developing more effective management strategies. The genome of the fungus was sequenced in 2007, providing a valuable resource for this research.