40 



Kerosene. — Valuable elms are frequently killed by the use of 

 pure kerosene on the trunks as a means of destroying the pupae. 

 The oil accumulates at the base of the tree and where used in 

 quantities, kills the roots. By substituting kerosene emulsion for 

 kerosene all danger will be avoided. 



Street Sioeepings. — The sweeping up and carting away of the 

 masses of pupae and larva? along with the other rubbish of the 

 streets is not an uncommon sight in infested cities. In a case 

 observed by the writer in July, 1898, quarts of the pupae were 

 carefully swept up in a public square and carted to the city dump. 

 In all such cases the sweepings should be burned or treated with 

 crude petroleum or kerosene emulsion. 



General Considerations. 



Outbreaks of the elm-leaf beetle are best dealt with by muni- 

 cipalities through the city forester, the park or the street depart- 

 ment. When feeding upon park and street trees the pest attacks 

 the common property of the citizens, and all may properly share 

 in the expense of combating it. With suitable apparatus and 

 insecticides, and competent men to make use of them, the elm-leaf 

 beetle can be kept under control and the infested trees preserved 

 from serious injury. The general plan adopted by the city of 

 Springfield is a most excellent one. Liberal appropriations are 

 made by the city to be expended under the direction of the city 

 forester, a man of exceptional fitness for the place. Two power 

 and a number of smaller hand spraying outfits have been pro- 

 vided, also a large stock of ingredients for making arsenate of 

 lead. A suitable force of men is engaged and spraying operations 

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

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

 by the larva? 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 mul- 

 tiply. 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 all 

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



