Chlorosis, leading to necrosis, of the lower leaves of pea plants infected with the root rot complex that consists of the pathogens that cause Aphanomyces root rot, Fusarium wilt, and Fusarium root rot. All three diseases alone will cause leaf chlorosis that begins with the lowest leaves on the plant and moves towards the top of the plant. Chlorotic leaves will turn necrotic as the plant matures. Chlorosis of leaves from the bottom of the plant to the top of the plant is most pronounced when Fusarium wilt is involved. Severe infection by Fusarium root rot will stunt the plant but, in general, will not kill the plant. Severe infections by Fusarium wilt or Aphanomyces root rot will generally kill the plants.
Photo Source: Lyndon Porter