152 STUDIES OF TREES 



August. In July they deposit their eggs in the outer 

 sapwood, immediately under the bark of the trunk and larger 

 branches. The eggs soon hatch and the gru])s feed on 

 the living tissue of the tree, forming numerous galleries. 

 The grubs pass the winter in a nearly full-grown condition, 

 transform to pupse in May, and emerge as beetles in June. 

 Remedies: The presence of the insect can be detected 

 by the small holes in the bark of the trees and the fine 

 sawdust which is ejected from these holes, when the insects 

 are active. It is important to emphasize the advisability 

 of detecting the fine saAvdust because that is the best indi- 

 cation of the actual operations of the hickory bark borer. 

 These holes, however, AA-ill not be noticeable until the 

 insect has completed its transformation. In summer, the 

 infested trees show wilted leaves and many dead twdgs. 

 Holes in the base of the petioles of these leaves are also 

 signs of the working of the insect. Since the insect works 

 underneath the bark, it is inaccessible for treatment and 

 all infested trees should be cut down and burned, or the 

 bark removed and the insects destroyed. This should be 

 done before the beetles emerge from the tree in June. 



PLANT LICE OR APHIDES 



These often appear on the under side of the leaves of 

 the beech, Norway maple, tulip tree, etc. They excrete a 

 sweet, sticky liquid called " honey-dew," and cause the 

 leaves to curl or drop. Spraying with whale-oil soap solu- 

 tion formed by adding one pound of the soap to five 

 gallons of water is the remedy. 



