SPECIES FOR STREET-PLANTING 41 



beauty of the white elm, it has a great many limitations. 

 The greatest objection to this tree is its susceptibility to the 

 attacks of more insect pests than any other one species 

 of tree. Some of its enemies are the- elm-leaf beetle, the 

 tussock moth, the leopard moth, elm borers, the elm-bark 

 louse, the spiny elm caterpillar, the bag worm, the gipsy 

 moth, and the brown tail moth. Of .these, the elm-leaf 

 beetle, the tussock and the leopard moths, are the most 

 destructive. The aspect of the elm-trees infested with the 

 beetle is one of devastation. They look as if they had been 

 swept by fire. 



The elm is adapted to wide streets, for it grows to a 

 great size. The characteristics that make it one of the 

 most beautiful of our native trees do not develop until the 

 tree is of considerable age. In the ordinary street, espe- 

 cially in places where the houses are close to the sidewalk, 

 the tree has no room. Standing as an individual, the Ameri- 

 can elm is very picturesque. Lining a broad avenue, the 

 trees form a perfect Gothic archway like a cathedral nave, 

 the beauty of which is not surpassed by any other species. 

 On the street of ordinary width the elm has no place. In 

 the case of this tree, too, more than most other species of 

 trees, provision must be made for regular and thorough 

 spraying to hold the insect enemies in check. 



European Elm (Ulmus campestris Linn.). The European 

 elm is sometimes used as a street-tree. In form it is better 

 suited for such planting, as it grows a smaller and more 

 rounded head. It also retains its foliage later in the sea- 

 son. However, the natural advantages of this tree are more 

 than offset by insect pests. The European elm is greed- 

 ily attacked by the elm-leaf beetle, the destructiveness of 

 which is greater than in the case of the native species. 



