CHAPTER XV 

 INSECTS AFFECTING SHADE TREES 



THE attractiveness of many of our towns and cities is due in 

 large measure to the beauty of the shade trees in streets and parks. 

 Occasionally insect depredations are such as to almost or quite 

 denude these trees of their leaves or to cause their death. The 

 object of this chapter is to discuss these pests and to offer either 

 remedial or protective measures. 



The Box-elder Bug. This is a bright-colored, black and red 

 bug (Leptocorisa trivittata Say) familiar to many of our farmers. 

 The red forms three broad lines over the black thorax, and the 

 hard parts of the wings are edged with red. The adult bug, 

 having passed the winter in this stage, lays eggs in the spring 

 wherever it happens to be. 



Many of the young, hatched from the eggs, never reach their 

 food. The insects are frequently found on the leaves and tender 

 twigs of the box elder, which habit gives them their name. It 

 may be seen, however, upon other trees and in various situations 

 (Fig. 261). 



Control. This being a sucking insect, it is difficult to control 

 it by spraying. Villages and cities should own strong spraying 

 outfits to protect their shade trees. In the fall, during cold days, 

 the bugs collect in large numbers and become, for the time being, 

 inactive. Such gatherings should be sought and the individ- 

 uals killed with boiling water. However, the box elder bug is 

 hardly ever sufficiently injurious to call for strenuous measures 

 of control. 



Box Elder Plant Louse (Chaitophorus negundinis Thos.). 

 This is a green louse which may be a serious pest to box elders 

 through sucking juices from the leaves and tender shoots, thereby 

 causing them to wither and die. Eggs are laid in the fall and hatch 

 before the leaves unfold. The lice gather about the opening buds 

 and attack the leaves as soon as they open. Winged forms appear 

 during the season to help dissemination. Parthenogenetic reproduc- 

 tion is the rule during summer, males and females appearing in 

 the fall. Eggs are then laid in the crevices in the bark and in the 

 axils of the buds. 

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