CHAPTER VI 

 THE CARE OF TREES 



STUDY I. INSECTS INJURIOUS TO TREES AND HOW 



TO COMBAT THEM 



In a general way, trees are attacked l)y three classes of 

 insects, and the remedy to be employed in each case 

 depends upon the class to which the insect belongs. The 

 three classes of insects are: 



1. Those that chew and swallow some portion of the 

 leaf; as, for example, the elm leaf l)eetle, and the tussock, 

 gipsy, and broA\Ti-tail moths. 



2. Those that suck the plant juices from the leaf or 

 bark; such as the San Jose scale, oyster-shell, and scurfy 

 scales, the cottony maple scale, the maple phenacoccus on 

 the sugar maples, and the various aphides on beech, Nor- 

 way maple, etc. 



3. Those that bore inside of the wood or inner bark. 

 The principal meml^ers of this class are the leopard moth, 

 the hickory-l^ark borer, the sugar-maple l^orer, the elm 

 borer, and the bronze-birch l^orer. 



The chewing insects are destroyed by spraying the leaves 

 with arsenate of lead or Paris green. The insects feed upon 

 the poisoned foliage and thus are themselves poisoned. 



The sucking insects are killed by a contact poison: that 

 is, by spraying or washing the afTected parts of the tree 

 with a solution which acts externally on the bodies of the 



134 



