Leaf rust is a fungal disease affecting wheat world-wide. Leaf rust is problematic becuase resistant varieties have limited use as new races (species) of the rust sporatically appear that have overcome resistance and spread. Later-maturity cultivars are more susceptible, along with cool and wet field conditions. Leaf rust infections result in poor grain fill and reduced kernal size and protein content. Leaf rust occurs in US wheat from mid-May through July and reappears in fall. The fungal spores reside in field soil and volunteer wheat over the summer.
Small, orangish-brown lesions are key features of leaf rust infections. These blister-like lesions are most common on leaves but can occur on the leaf sheath, which extends from the base of the leaf blade to the stem node. Lesions caused by leaf rust are normally smaller, more round, and cause less tearing of the leaf tissue than those caused by stem rust.
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