appear on the surface of wheat leaves, a large number of urediospores may be liberated after rupture of the uredinia
and then be spread by air, which may result in secondary infections.
abaxial, brown, rounded, scattered, 0.8-2 x 0.6-1 diameter.
The symptoms initially appear as small yellow pustules containing uredinia
, which may cover large portions of the abaxial leaf surface.
hypophyllous, yellowish, minute, covered with ruptured epidermis, pulverulent, scattered over the whole leaf surface, surrounded by numerous incurved paraphyses.
Beginning in July 2010, and annually since, symptoms of brown to black foliar spotting with margins of chlorosis and signs of abundant uredinia
production were observed on plots of 3 year-old 'Alamo' and 9 year-old 'EG1101' switchgrass, established at the Leveck Animal Research Facility in Starkville, Mississippi (Figures.
are observed initially in the dark dots that progressively acquire a light brown to red brown color and open in a minute pore releasing the colorless urediniospores, which become tan and accumulate around the pores (Balardin, 2002; Yorinori et al., 2004; Almeida et al., 2005).
The rating scale of infection responses in these evaluations consisted of four classes: R (resistant), MR (moderately resistant), MS (moderately susceptible), and S (susceptible) determined primarily on the basis of the size of uredinia
. Based on natural field infection in Colorado, Hatcher is moderately resistant to stripe rust (caused by Puccinia striiformis Westend.; 4.3 score, 1 = resistant and 9 = susceptible, n = 4 evaluations).
Two different components of reproductive output corresponding to different stages of the pathogen's life cycle, formation of uredinia
(pustules) on leaves and production of urediniospores by the uredinia
, are modeled as functions of the strains' inoculum and uredinial densities, respectively.
amphigenous, subepidermal, golden brown to blackish brown, present in rows, scattered but somewhat compact, naked, 0.06-0.11 x 0.094-2 mm.