464 NATURE STUDY AND LIFE 



Peach-Leaf Curl, Exoascus deformans. By attacking the leaves, 

 blossoms, and growing twigs of the peach this fungus sometimes 

 causes the loss of the entire crop, and great damage to the trees. If 

 present in the neighborhood, the pupils will have no difficulty in 

 finding specimens for study. Peach-leaf curl is so easily prevented 

 by spraying that there is no excuse for allowing an orchard to be 

 affected by it. 



Peach Yellov/s. No fungus has been discovered in connection 

 with this disease, although it has been sought for with great diligence. 

 Expert testimony inclines to the view that it is not due to a germ of 



FIG. 192. PLUMS DESTROYED BY BROWN ROT 



any kind. Still it is clearly contagious, is transmitted by seeds or 

 buds, and probably by the mere presence of a diseased tree in the 

 orchard. How these facts can be explained on any other theory 

 than that of the germ origin of the disease, it is difficult to imagine. 

 Affected trees ripen their fruit prematurely, and many of the buds 

 intended for the following spring burst into a spindling, sickly, yellow 

 growth during the summer. No tree has been known to recover 

 when once attacked, and since the fruit is worthless, the sooner it is 

 uprooted and burned the better. Laws compel a man to do this in 

 a number of states where peach raising is an important industry. 

 Other garden fungi that should be observed and studied are : 

 Downy Mildew, Peronospora viticola. This fungus attacks 

 grapes, especially vines allowed to grow without proper pruning. 



