INSECT PESTS 



235 



as food for stock, and this will pay the cost of picking 

 up all fallen fruit once or twice each week. 



The Woolly Aphis or Louse (Schizoneura lanigera) 

 (Figure 124, a, rootlet showing galls; b, wingless aphis; 

 c, winged aphis; d-g, structural details; b-g, magnified) 

 Although this is commonly known as the root louse 

 and generally found on the roots of the apple tree, 

 it often causes much injury to the trunk and main 

 branches. It is a small insect, about one-sixteenth to 



Fig. 124-The Woolly Aphis 



one-eighth of an inch long, and more or less covered 

 with a cottony, nearly white, substance, whence comes 

 its name. It attacks the trunk and the branches in 

 patches, sucking the juices and causing black, canker- 

 like places which may spread, often destroying the 

 limb. It most commonly attacks parts that have been 

 previously injured in some way, as in climbing about 

 .to pick the fruit, in pruning, or an injury by the black 

 rot fungus increasing its injuries. The roots of young 

 trees are often seriously injured by this pest, baffling 

 all efforts of the grower to make them grow, and the 

 cause of this condition not being known until the tree 

 is dug up. 



