The mold-like pathogen that causes the disease, infects the roots and underground stems of susceptible pea plants and other legumes, rotting them and causing stunted growth, lesions, wilted leaves and other symptoms. Fungicides aren't an option, so growers must either avoid planting in fields with a history of the disease or switch to growing non-host crops until pathogen numbers drop to acceptable levels. "Aphanomyces is obviously a root disease and it has been a problem with peas for 50 years. What has historically been the solution because it was really in the fresh pea industry, and historically the solution has been to move. If you think about pea production in the United States, it started in New Jersey with fresh peas, they moved to Minnesota and that got infected and so they moved to the Pacific Northwest.