. Bulletin of the Department of Agriculture. Agriculture; Agriculture. I' "J H 111 m A, 5 per cent. B, 10 per cent. C, per cent. D, 40 per cent. E, 65 per cent. F, 100 per cent. Fig. 1.—Scale for estimating rust, illustrating six degrees of rustiness used in estimating the percentage of stem-rust infection. The shaded spots represent rust, and the figures represent approximately the rust percentages computed on the basis of the maximum of surfaces covered by rust as shown in the 100 per cent figure (F). Figure F in the diagram represents 37 per cent of actual rust-covered surface
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. I' "J H 111 m A, 5 per cent. B, 10 per cent. C, per cent. D, 40 per cent. E, 65 per cent. F, 100 per cent. Fig. 1.—Scale for estimating rust, illustrating six degrees of rustiness used in estimating the percentage of stem-rust infection. The shaded spots represent rust, and the figures represent approximately the rust percentages computed on the basis of the maximum of surfaces covered by rust as shown in the 100 per cent figure (F). Figure F in the diagram represents 37 per cent of actual rust-covered surface and is arbitrarily selected as 100 per cent. The other percentages are in terms of figure F. fection centers. It was evident from the results obtained that the latter method was sufficiently dependable to warrant the discontinu- ance of urediniospore sprays. The common barberry {Berheris vulgaris L.; see PL I, fig. 2), planted south of the rust nursery plats, furnished some secial infection in 1915, 1916, and 1917. Straw, bearing telia of stem rust, was placed around each shrub in the fall, so as to provide the necessary telio- spore material to infect the barberry leaves in the spring. The final field notes were taken during the latter part of June or early in July, at the time the nursery was harvested. These included the percentage of stem rust, estimated in accordance with the scale shown in figure 1 and used by the Office of Cereal Investigations of the Bureau of Plant Industry, United States Department of Agri- culture. Notes on the type of head, plumpness of grain, and other characters also were Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of Agriculture. [Washington, D. C. ?] : The Dept. : Supt. of Docs. , G. P. O.
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