Apple. 243 



or fruit of the apple. They ripen in spring, and consequently it 

 is at this season of the year that the apple trees must be pro- 

 tected. Unfortunately, when a tree has once become infected, 

 it seems that the mycelium of the rust may remain in the buds 

 and branches for years, and in the spring when the young leaves 

 have formed, the characteristic yellow spots may again appear, 

 although no new infection has taken place. The disease is 

 sometimes so serious that the tree loses all its foliage, and this 

 alone would ruin the crop, although the apples themselves may 

 not be attacked. 



Treatment. It is difficult to combat the apple rust successfully. 

 Since apple trees are attacked by spores which are produced upon 

 cedar trees, it naturally follows that by removing all cedars we 

 also remove the source of the disease. Cutting and burning 

 the cedar-apples before the appearance of the yellow horns will 

 answer the same purpose. In many cases, however, such a 

 course is impracticable on account of the abundance of the 

 trees. Scribner advises l the removal of all badly diseased trees 

 in the orchard, as well as the worst branches on trees which are 

 not seriously attacked. Then, to prevent further injury from 

 the fungus, spray both large and small trees with some good 

 fungicide, as the Bordeaux mixture. The applications should 

 be made as soon as the first leaves appear. Two applications 

 should be sufficient, the second one being made eight or ten days 

 after the first. During rainy seasons it may be well to repeat 

 the operation a third time. The planting of resistant varieties 

 is one of the best methods of escaping the disease. See QUINCE. 



Scab (Fusicladium dendriticum, Fckl.). Description. This 

 fungus attacks the fruit and the leaves of both apple and pear 

 trees. Upon the fruit it forms dark, circular spots, the largest 

 being about half an inch in diameter (Fig. 38). These spots 

 are often close together or unite to form surfaces which may 

 extend over a considerable area. The centers of the spots are 

 dark brown or black in color, but at the edges there is a light 

 gray or white circle. This appearance is due to the separation 

 of the outer skin, or cuticle, from the tissue beneath. When 

 the diseased area is large, it generally cracks, and then the 

 hard, brown tissue within the apple may be seen (Fig. 39). 

 Growth is checked in the diseased portions and the fruit is 



1 Orchard and Garden, 1890, Vol. xii. July, 134. 



