102 



SPRAYING CROPS 



FUNGUS ENEMIES 



There are at least three fungous diseases of young 

 nursery trees to prevent which spraying pays. They 

 are : ( i ) the Pear Leaf-blight, which affects quince 

 as well as pear stocks; (2) the Powdery Mildew, 

 which occurs upon apple and cherry, and (3) the 

 Leaf-blight or Leaf-spot of the plum and cherry. 



According to Dr B. T. Galloway, the body or vege- 

 tative system of the Pear Leaf-blight consists of 



Leaf =skeleton izer 



larva; part of back, magnified to show markings; r, head and front part 

 of larva, magnified; moth, magnified. (After Riley) 



very minute, short, colorless filaments, which grow 

 between and through the delicate cells of the leaf, 

 ''destroying all the latter with which it comes in con- 

 tact, and using their nourishment for building up its 

 own structure. As a result of this process, the leaf 

 shows, here and there on the surface, small, more or 

 less circular, dark brown spots ; these spots rapidly 

 enlarge, and by running together soon cause the entire 

 leaf to turn brown and then fall off. Before the latter 



