Affected plants are stunted and yellow, lose lower leaves and die prematurely. The lower stem turns black or brown. Roots are pinched off and rotted. This disease is characterized by poor or no emergence, and those plants that do emerge typically collapse before the first true leaves unfold. Pythium species are the most common fungal cause of seedling blight in field peas.
Infected seeds become soft and watery, with fungal hyphae, or strands, emanating from the seed.
Cool soil temperatures and wet soils favour the development of this disease. Sclerotinia stem and pod rot A serious pathogen of canola, Sclerotinia sclerotiorum , is less of a problem in field peas. Symptoms of this disease are soft stems and pods with a cottony white mould and hard charcoal-like resting bodies, called sclerotia, on the inside or outside of the stems. During periods of high soil moisture, the sclerotia grow golf tee-like structures that disperse spores into the air and onto the plant. Disease Levels in Direct Versus Conventional Seeding Systems Research on whether disease levels increase or decrease under direct seeding has produced seemingly contradictory results.