Forest Protection 175 



bark and passes on to another tree. A great number of 

 these galleries will girdle the tree and interfere seriously 

 with the movement of sap. 



If the insects are in sufficient numbers, the tree is killed. 

 The needles turn red the first year, a number of secondary 

 enemies attack the weakened tree, fungi enter the wounds 

 and in three or four years the tree is worthless. 



The beetle is best kept in check by cutting the infected 

 trees, for it is in these weakened and dying trees that 

 they multiply. The trees felled should be peeled or 

 placed in a pond to kill the larvae. When the cutting can 

 be carefully regulated, the insects can be controlled easily 

 in this way, — for they must be present in great numbers 

 to successfully attack living trees. 



The spruce-destroying beetle 



The spruce of the northwestern part of the United 

 States finds its most formidable enemy in the Dendroctinus 

 piceaperda, the spruce-destroying beetle. It has destroyed 

 vast quantities of spruce timber in Maine, New Hampshire 

 and West Virginia and is still active in those regions. 



According to Hopkins "The adult varies from ^ to 

 i^- inch in length and from t$ to y\ bich i Q width. It 

 also varies in color from light yellowish brown in the 

 younger specimens to reddish brown or nearly black in 

 mature stages. The egg is small and pearly white like 

 that of most bark beetles." 



The larva hatches out a minute, white legless grub and 

 feeds on the inner bark till it increases to a size slightly 

 larger 'than the adult. It may be distinguished by a dark 

 yellowish brown space on the upper surface of each of the 



