. Diseases of economic plants . Plant diseases. 394 DISEASES OF ECONOMIC PLANTS the Southern States from North CaroHna to Florida, and west to Texas, and is yearly noted in new localities. Owing to the all-important position the cowpea occupies in southern agriculture as a nitrogen crop, where the best rotation demands its frequent recurrence upon the same soil, the disease is of pecuhar moment. No remedy is known except the use of the iron cowpea, the re- sistance of which was noted by Mr. T. S. Williams of South Car- olina in 1900, and fur- ther tested by W. A. Orton of the United States Dep
. Diseases of economic plants . Plant diseases. 394 DISEASES OF ECONOMIC PLANTS the Southern States from North CaroHna to Florida, and west to Texas, and is yearly noted in new localities. Owing to the all-important position the cowpea occupies in southern agriculture as a nitrogen crop, where the best rotation demands its frequent recurrence upon the same soil, the disease is of pecuhar moment. No remedy is known except the use of the iron cowpea, the re- sistance of which was noted by Mr. T. S. Williams of South Car- olina in 1900, and fur- ther tested by W. A. Orton of the United States Department of Agriculture. Leaf spot {Amerosporium ceconomicum Ell. & Tracy). — This disease is readily distinguished from cercosporose by the fact that the spots are circular, are of shiny white- ness, and are studded all over with httle black pycnidia, smaller than an ordinary pinhole. Fig. 170. The disease is often abundant, but is usually not so serious as cercos- porose. Powdery v:uldew (Erysiphe polygoni DC). — The white spots of this mildew are strictly circular when young, but as they enlarge they coalesce and cover the whole upper surface of the leaves with a white Fig. 171. — Cowpea leaflet ST)ttoi wHli poW' dery mildew. ^ 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 Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
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Keywords: ., bookauthorstevensf, bookcentury1900, bookdecade1910, bookyear1910
