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Symptoms and Signs

On wheat and other grass hosts:
Plants do not usually show obvious disease symptoms until 7 to 15 days after infection when the oval pustules (uredinia) of powdery, brick-red urediniospores break through the epidermis (Figures 1, 2). Microscopically, these red spores are covered with fine spines (Figures 3, 4). The pustules may be abundant and produced on both leaf surfaces and stems of grass hosts. Later in the season, pustules (telia) of black teliospores begin to appear in infected grass species (Figure 5). Microscopically, teliospores are two celled and thick walled (Figure 6).


Figure 1	Figure 2	Figure 3

Figure 4	Figure 5	Figure 6

On barberry and other alternate hosts:
Pycnia appear on barberry plants (Figure 7) in the spring, usually in the upper leaf surfaces. They are often in small clusters and exude pycniospores in a sticky honeydew (Figure 8). Five to 10 days later, cup-shaped structures filled with orange-yellow, powdery aeciospores break through the lower leaf surface (Figure 9). The aecial cups are yellow and sometimes elongate to extend up to 5 mm from the leaf surface (Figure 10). Microscopically, aeciospores have a slightly warty surface (Figure 11).


Figure 7	Figure 8	Figure 9

Figure 10	Figure 11

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