File:Diseases of field crops (1941) (20347185203).jpg

Title: Diseases of field crops
Identifier: diseasesoffieldc121smit (find matches)
Year: 1941 (1940s)
Authors: Smith, Ralph E. (Ralph Eliot), 1874-1953
Subjects: Plant diseases
Publisher: Berkeley, Calif. : College of Agriculture, University of California
Contributing Library: University of California, Davis Libraries
Digitizing Sponsor: University of California, Davis Libraries

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64 California Agricultural Extension Service (Gib. 121 black spore pustules of the fungus Septoria tritici. Tin* leaves become blighted, the plants weakened, the grain shriveled, and the yield reduced. The fungus flourishes in cool, moist weather on early-sown wheat. No control method is known. Crop rotation is beneficial. Stem Rust.—This rust appears about the time of heading and attacks both the leaves and the leaf sheaths, which enclose the stem (fig. 31, p. 51). The pustules are long and dark red at first, and their edges turn back in ragged margins ; later the pustules turn black. This color change
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Fig. 40.—Take-all, or foot rot, on wheat. (Courtesy of the New South Wales Department of Agriculture; from Bui. 511.) is due to the fact that two different types of spores are produced (tig. 38), The plants may be badly injured and killed. In most places this rust fun- gus, Puccinia graminis, passes one stage of its development on the com- mon barberry, and the eradication of such bushes helps to control wheat rust. In California, this host is not attacked, and the rust lives the year round on wheat, barley, and certain grasses. No method of field treatment for wheat rust has been known until recently, when dusting the fields with sulfur by means of airplane has shown some promise; but even this does not appear economically feasible. The first applications of sulfur should be made just as soon as pustules of rust appear and must be repeated at 7- to 10-day intervals, using 15 to 20 pounds of dusting sulfur per acre for each application. Seed treat- ment has no effect on rusts.

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