Pea Root Rots

The causative agents of the disease are a complex of pathogens, including species of the genus Fusarium, among which F. solani f. sp. pisi and F. avenaceum are the most aggressive, as well as oomycetes such as Aphanomyces euteiches f. sp. pisi and Pythium ultimum, and fungi of the genus Rhizoctonia. Pathogens often act synergistically, causing damage to roots and the root collar, which is accompanied by tissue darkening, sliminess, or dry rot.

Symptoms include overall stunting, premature ripening, and a decrease in the productivity of nitrogen-fixing bacteria. Fusarium infections are often accompanied by vascular browning of the stem and specific mycelial growth under high humidity, while Aphanomyces root rot is characterized by water-soaked, golden-brown lesions.

Resistance to root rots in peas is primarily quantitative in nature. Breeding is complicated by the linkage of resistance traits with undesirable genes, such as the A locus, which is responsible for anthocyanin pigmentation. Modern work with genetic material relies on the use of molecular markers and the search for cultivars with high field resistance.