The characteristic symptom is of parallel rows of yellowish orange coloured pustules on the leaves of adult plants. epidemics of yellow rust often start as individual plants showing symptoms, usually in the autumn. These usually develop slowly over winter and are often missed until the early spring when small patches or foci of infected plants can be seen in fields. The yellow to orange coloured pustules on leaves in the very early stages are very difficult to distinguish from brown rust However, yellow rust lesions tend to spread as a band across young leaves, often with a yellow band on the leaf moving ahead of the sporulating lesion On older leaves pustules tend to occur in obvious stripes Severe attacks quickly give rise to chlorosis and later necrosis of leaves Infected leaves can rapidly desiccate in MayJune if weather conditions are warm and dry. In severe attacks yellow rust infection of the ears can occur, resulting in the formation of masses of spores between the grain and the glumes. At the end of the season, secondary black spores teliospores are sometimes produced amongst the stripes of pustules

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