. Diseases of economic plants. Plant diseases. Vegetable and Field Crops 159 Minor diseases Orobanche is sometimes parasitic on beans. Sunscald ^^^ produces discoloration. Powdery-mildew {Erysiphe polygoni DC.) often gives a rusty color to the pods. Leaf-blotch {Cercospora cruenta Sacc.) occurs only upon the foliage as brownish patches, causing the leaves to fall away. The spots are large, angular, and limited by the veins. Leaf-spot {Isar- iopsis griseola Sacc.) is chiefly limited to the foliage, produc- ing small, angular spots, over the under surface of which the fungus forms a gray, moldy


. Diseases of economic plants. Plant diseases. Vegetable and Field Crops 159 Minor diseases Orobanche is sometimes parasitic on beans. Sunscald ^^^ produces discoloration. Powdery-mildew {Erysiphe polygoni DC.) often gives a rusty color to the pods. Leaf-blotch {Cercospora cruenta Sacc.) occurs only upon the foliage as brownish patches, causing the leaves to fall away. The spots are large, angular, and limited by the veins. Leaf-spot {Isar- iopsis griseola Sacc.) is chiefly limited to the foliage, produc- ing small, angular spots, over the under surface of which the fungus forms a gray, moldy covering. It has been ob- served in many states, and is most injurious in the South.^^'' Wilt due to Pseudomonas sol- anaceariim has also been re- p ported. Root-knot (nema- todes) is injurious in some localities. Streak. — Dark spots occur on stems, leaves, and pods. The cause is un- known. Mosaic ^^^ in general character resembles tobacco j-^^ g^ _ j^.^^_b^^^ p^^^ ^^^^^. mosaic. It appears to be of ing pod-blight. AfterHalsted. wide distribution and to be communicated through the seed. Resistant strains should be grown. BEET, CHARD, MANGOLD, MANGELS Cercospora Leaf-spot i9i~i94 (^Cercospora heticola Sacc). — This, one of the several leaf-spots upon the beet, is very widespread in the eastern and middle states. Very few fields are entirely free from it. It occurs upon all varieties, but is especially injurious to the sugar 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- [from old catalog]; Hall, John Galentine, 1870- [from old catalog] joint author. New York, The Macmillan company


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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1921