Septoria tritici

Septoria tritici is a fungal pathogen that causes Septoria tritici blotch (STB), a major disease of wheat crops. It is also known as Mycosphaerella graminicola and Zymoseptoria tritici. The disease is prevalent in many wheat-growing regions worldwide, causing significant yield losses.

Life Cycle

The life cycle of Septoria tritici begins with the germination of ascospores or conidia on the wheat leaf surface. The fungus then penetrates the leaf cuticle and colonizes the leaf tissue, causing necrotic blotches. The fungus reproduces asexually within the leaf, producing conidia that are spread by rain splash to other leaves. Sexual reproduction occurs in the leaf blotches, resulting in the production of ascospores that are released into the air and can infect other wheat plants.

Symptoms

The primary symptom of STB is the appearance of necrotic blotches on the wheat leaves. These blotches are initially small and chlorotic, but they enlarge and become necrotic as the disease progresses. Within the blotches, black pycnidia can be seen, which are the fruiting bodies of the fungus.

Management

Management of STB involves a combination of cultural practices, resistant varieties, and fungicide applications. Cultural practices include crop rotation and the removal of infected crop residues. Resistant wheat varieties are available, but the fungus can overcome resistance quickly due to its high genetic variability. Fungicides are effective, but their use should be carefully managed to avoid the development of fungicide resistance.

Impact

STB is a major disease of wheat, causing significant yield losses in many wheat-growing regions. The disease can reduce grain yield and quality, and increase the costs of production due to the need for fungicide applications.

See Also

• Wheat diseases
• Fungal plant pathogens and diseases
• Mycosphaerella