Pea ("Pisum sativum") is the crop where Aphanomyces causes the greatest economic damage. Aphanomyces root rot can account for yearly losses of about 10% in the fields where it occurs, and may cause losses of entire fields in conditions that are favorable to the pathogen. In agricultural regions that produce large amounts of susceptible crops and have favorable weather conditions for "A. euteiches", careful monitoring is of paramount importance. Such regions include the American Midwest, particularly the Great Lakes region. In areas where peas are grown for processing, widespread "Aphanomyces" infection can cause processing (canning) factories to relocate, a considerable threat for local economies. In fact, prevalence of Aphanomyces root rot has ultimately shifted pea production in the United States from being predominantly in the Midwest and Eastern parts of the country to drier states such as Idaho, Washington, and Oregon where "A. euteiches" is still common but conditions are less favorable.