. Bulletin. Agriculture. 10 THE CURLY-TOP OF BEETS. together instead of opening out and spreading (PI. II, fig. 2, and PI. Ill, fig. 1). The foliage is generally of a dark, dull-green color and quite brittle, though thick and leathery in appearance. In severe cases, especially among young plants, the outer leaves soon become yellow, die, and turn brown; the inner whorls follow, until the entire plant is killed. The roots throw out dense masses of rootlets from the two spiral grooves; hence the names " hairy-root" and " whiskered ; (See PI. II, figs. 1 and 2.) The root
. Bulletin. Agriculture. 10 THE CURLY-TOP OF BEETS. together instead of opening out and spreading (PI. II, fig. 2, and PI. Ill, fig. 1). The foliage is generally of a dark, dull-green color and quite brittle, though thick and leathery in appearance. In severe cases, especially among young plants, the outer leaves soon become yellow, die, and turn brown; the inner whorls follow, until the entire plant is killed. The roots throw out dense masses of rootlets from the two spiral grooves; hence the names " hairy-root" and " whiskered ; (See PI. II, figs. 1 and 2.) The root itself looks tough and fibrous and in many cases be- comes sprangling. When pulled up, masses of soil cling to the hair-like rootlets and are with difficulty shaken off. The growth of every portion of the plant is checked, if not entirely arrested. In many cases the leaf - curl assumes an alternative form. In- stead of an inward curl, the leaf as a whole becomes strongly re- tracted and each por- tion between the larger veins is puffed out. This results in a blis- tered or "savoyed'' ef- fect. In this latter type the vein symptoms are not usually so pro- nounced. Sometimes the two types are com- bined; the leaf as a whole is then retracted, but the margin curls inward (figs. 2 and 3). Frequently wine-colored stains develop in the form of small circular spots over the surface of leaves of mangel- wurzels and garden beets, but no local discoloration has been noted on sugar beets except a faint mottling of young leaves which can only be seen by transmitted light. 181. Fig. 1.—Healthy sugar beets, Vilmorin type. (For com- parison with beets affected by curly-top.). 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. Bureau of Plant Industry. Washington : G. P. O.
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