Severe epidemics develop under wet conditions and temperatures of approximately 20ºC. Yield losses of 5-15% are common where the disease is established and if wet conditions continue through pod development. The pathogen infects leaves, stems, flowers and pods.
Early symptoms on leaves appear as small purplish spots with irregular margins. On older leaves, lesions enlarge, causing the dehydration of plant tissues. Infected seeds may be asymptomatic or may become shrunken and discolored. Infected seedlings often develop symptoms only on the stem base where cotyledons attach.
Scout in cool, wet conditions for early symptoms (such as small leaf spots). Later in the season, check blossoms for petal lesions or blossom drop. It is estimated that for every 10% of infected stem area, about 5% yield loss occurs.
To prevent the infection of pea crops, plant disease-free certified seed. Avoid growing peas more than once in four years and avoid adjacent fields where peas have been grown recently. Till under infected crop residue to reduce disease inoculum. Vitaflo 280 and Trilex AL seed treatments protect against seed-borne Ascochyta.