SOME DISEASES OF FRUITS 



231 



it may cause the little apples to fall. In ordinary seasons 

 this disease is well controlled by spraying at intervals of 

 two weeks with Bordeaux mixture. 



Bitter-rot of the apple. As the name implies, an apple 

 attacked by this disease has a bitter taste. Bitter-rot is 

 worst in moist, warm 

 weather. It begins as 

 a small spot and rapidly 

 spreads from fruit to 

 fruit. Later the affected 

 area becomes flattened 

 or sunken. A few days 

 after the rot has begun, 

 there are little circles of 

 black dots beginning to 

 appear at the center 

 of the diseased spot. 

 These little dots contain 

 the spores which will 

 spread the disease. This 



fungUS also makes in- FIG. 158. PEAck TREE NOT SPRAYED 

 juries, Called Cankers, Injured by leaf-curl. 



on the branches of the apple tree. 



It is estimated that bitter-rot of apples has repeatedly 

 caused damage to the extent of ten million dollars a year. 

 It may be controlled by the use of Bordeaux mixture. 



Fire-blight of the pear and apple tree. The common 

 blight of pear and apple trees, which kills and blackens 

 the leaves and sometimes kills the pear tree, is caused by 

 germs, called bacteria. This disease also .kills the bios- 



