Didymella pinodes in pea

Didymella pinodes (syn. Mycosphaerella pinodes) is a hemibiotrophic fungal plant pathogen and the causal agent of ascochyta blight on pea. It is infective on several species such as Lathyrus sativus, Lupinus albus, Medicago spp., Trifolium spp., Vicia sativa, and Vicia articulata, and is thus defined as broadrange pathogen.

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Necrotic lesions caused by Didymella pinodes on field pea leaves two weeks after infection.

Symptoms

Symptoms include lesions on leaves, stem and pods of plants. The disease is difficult to distinguish from blight caused by Ascochyta pisi, though D. pinodes is the more aggressive of the two pathogens.

Epidemiology

The disease cycle starts with dissemination of ascospores after which germination pycnidia rapidly develop. Pycnidiaspores quickly disperse by rain splashes are responsible for reinfection over short distances. Consequently, production of pseudothecia is initiated on senescent tissues. After rainfall, ascospores are released from the pseudothecia and disperse by wind over long distances.