138 DISEASES OF ECONOMIC PLANTS 



plies. Its distinguishing characters are given by Smith as 

 follows : ^ — 



" Rosette clearly belongs to the same type of diseases as 

 yellows, but its first stages are more striking and its prog- 

 ress is much more rapid. It may first attack part of the 

 tree and then the remainder, the same as the yellows, but 

 it is more likely to appear at once on the whole tree, and 

 generally in early spring. In trees attacked in this manner, 

 all of the leaf buds grow into compact tufts or rosettes. 

 These rosettes, though seldom more than two or three 

 inches long, usually contain several hundred small leaves. 

 A tree thus attacked always dies during the following winter 

 or autumn. When part of a tree is thus attacked, that 

 part dies as above described, and the remainder shows 

 symptoms the next spring, to die in turn after al)out six 

 months. 



" The prevailing color of the foliage is yellowish green or 

 olivaceous. The older leaves at the base of the tufts are 

 largest, and frequently grow to a length of several inches, 

 but have inrolled margins and a peculiar stiff appearance, 

 due to the fact that they are straighter than healthy leaves. 

 These outer leaves turn yellow in early summer and drop 

 as readily as though it were autumn, while the inner leaves 

 of the rosette are still green and delicate. The compact 

 bunching of the leaves is very conspicuous, and makes the 

 trees look quite unlike those affected by yellows. Where 

 a tree is attacked in all parts, it matures no fruit. In all the 

 cases which have been noticed the fruit liorne by affected 

 trees either shrivels while green and drops off, or else ripens 

 naturally. 



1 Smith, E. F., U.S. Dept. Agr. Farmers' Bui. 17, p. 14. 



