Didymella pinodes

A fungal pathogen affecting legumes

Didymella pinodes is a fungal pathogen that primarily affects legumes, particularly pea plants. It is known for causing the disease commonly referred to as Ascochyta blight, which can lead to significant agricultural losses.

Morphology

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Symptoms of Didymella pinodes on pea plants

Didymella pinodes is characterized by its production of pycnidia, which are small, flask-shaped fruiting bodies. These structures produce conidia, which are the asexual spores responsible for the spread of the fungus. The conidia are hyaline, elliptical, and typically measure 10-15 µm in length.

Life Cycle

The life cycle of Didymella pinodes involves both sexual and asexual stages. The sexual stage occurs when ascospores are produced within pseudothecia, which are larger fruiting bodies that develop on infected plant debris. These ascospores are released into the environment and can initiate new infections.

The asexual stage is marked by the production of conidia within pycnidia. These conidia are dispersed by rain splash and wind, leading to secondary infections throughout the growing season.

Symptoms

Infected plants exhibit a range of symptoms, including leaf spots, stem lesions, and pod rot. The leaf spots are typically dark brown with a concentric ring pattern. Stem lesions can girdle the stem, leading to wilting and plant death. Pod rot results in shriveled and discolored seeds, reducing yield and quality.

Epidemiology

Didymella pinodes thrives in cool, wet conditions, which facilitate the spread of conidia. The pathogen can survive on infected plant debris in the soil, serving as a source of inoculum for subsequent growing seasons. Crop rotation and removal of plant debris are essential management strategies to reduce the incidence of the disease.

Management

Effective management of Didymella pinodes involves an integrated approach, including the use of resistant cultivars, crop rotation, and fungicide applications. Monitoring environmental conditions and applying fungicides during periods of high risk can help control the spread of the pathogen.

Related pages

• Ascochyta blight
• Legume
• Fungal plant pathogens