Diseases

Ascochyta blight of faba bean

Vicia faba L. var. equina St.-Amans

A fungal disease caused by the highly specialized pathogen Ascochyta fabae (teleomorph Didymella fabae), which affects exclusively faba bean.

In the reference 11 varieties crop Horse bean, where this is mentioned in the description.

The disease affects all aerial parts of the plant. Symptoms manifest as two types of brown spots: large concentric spots without a border and round or elongated spots with a dark red or dark brown margin. Pycnidia—small black dots that serve as the fungus's sporulation organs—form in the center of the affected areas.

A distinctive feature of Ascochyta blight is that the spots spread to both sides of the leaf, which allows for visual differentiation from chocolate spot. The pathogen exhibits significant variability in virulence across different regions. The genetic resistance of the crop is polygenic with low heritability, which complicates breeding and makes cultivar effectiveness dependent on the interaction between genotype, pathogen, and environmental conditions.

General information about the subject — on the page Ascochyta blight.

Sources8

Varieties of Horse bean mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.