ABSTRACT
Symptoms HAULM: Ring rot symptoms may first appear 60-70 days after planting but disease expression is dependent on temperature and potato cultivar. Under warm growing conditions all of the plant symptoms may be detected, while under cooler conditions, few or no symptoms may be seen. The first symptoms appear as a pale yellow mottling in the lower leaves (8), which usually show signs of wilting. Leaf margins often curl upward and roll inward, and eventually dead brown areas develop. These symptoms usually begin in the lower leaves and proceed upward as the disease progresses. Leaf yellowing may intensify, producing bars of bright yellow tissue between the veins. Symptoms may first be limited to one stem but with severe infection, the whole plant may wilt and die. At an advanced stage, a brown ring can be visible in a cut stem and a cheesy exudate squeezed out from the vascular ring. In cool
STOLONS: No distinct symptoms are normally seen.
