Spots with pycnidia on leaves of Vicia faba L.

LEAF SPOTS at first yellow brown, later gray-brown, with concentric zones, 3-10 mm diam, surrounded by a distinct, dark brown border, present on leaves, stems, pods and seeds.

PYCNIDIA (p) yellow brown, pale brown to dark brown, spherical, rarely lenticular, 100-250 µm diam, with a circular pore (ostiolum), 20-30 µm diam, immersed in the leaf tissue, distributed on the whole infected area or conglomerated in concentric discs, sometimes concentrated in small groups, or even connected with each other.

CONIDIA (c) cylindrical, oblong-ellipsoidal, ellipsoid-clavate, or egg-shaped, straight or slightly curved, 2(-4)-septate, not or slightly constricted at the septa, 9.5-16(-19) x 3-4.5 µm.

PLANT HOST AND DISTRIBUTION. Ascochyta pisi affects living leaves of different plant species of the family Fabaceae, including Glycine max (L.) Merr., Lathyrus niger (L.) Bernh., L. sylvestris L., L. vernus (L.) Bernh., Pisum sativum L., and Vicia faba L. (Salata 2002).

This fungus occurs on many members of the family Fabaceae growing in Australia, Asia, Europe, north Africa, as well as North and South America (Salata 2002).

NOTES. Ascochyta pisi is a seed-borne pathogen and primary lesions on the first leaves come from infected seeds (Smith et al. 1988). This pathogen can also cause pre- and post-emergence damping-off and dwarfing, but does not initiate foot rotting symptoms.

Ascochyta pisi is transmissed via rain-splashed conidia, infected host debris, an infected seeds (Smith et al. 1988).

REFERENCE

Salata B. 2002. Polskie gatunki grzybow mitosporowych z rodzaju Ascochyta. Wydawnictwo UMCS. Lublin. 121 pp.

Smith I. M., Dunez J., Lelliott R. A., Phillips D. H., Archer S. A. 1988. European handbook of plant diseases. Blackwell Scientific Publications.