300 BOARD OF AGRICULTURE. [Pub. Doc. 



are begun as soon as the beetles bepfin to feed and lay in the 

 spring. Spraying is continued until into July, or as long as 

 injury by the larvae continues. Infested trees on private 

 estates are sprayed by the city's employees, and the expense 

 charged to the owner. By this method the damage by the 

 beetle is reduced to a minimum and the preservation of the 

 elms secured. A similar method on a somewhat smaller 

 scale is followed at Northampton, with most excellent results. 

 Damage by the elm-leaf beetle emphasizes the desirability 

 of planting a variety of trees in parks and along streets, in 

 order to escape those insects which are confined to a few 

 food plants. Large numbers of a single species of tree, 

 planted thickly, give the insects attacking that species an 

 excellent opportunity to multiply. By planting a great 

 variety of trees, taking care that only small numbers of a 

 single species are placed near together, a large amount of 

 future damage by insects may be prevented. In every case 

 the European elm should be planted sparingly, if at all. 



