THE ELM LEAF BEETLE. II 



will no longer pay to make it up each time from lead acetate 

 and arsenate of soda. The arsenate of lead made by the Merri- 

 mac Chemical Co., Boston, Mass. ; Schoonmaker & Son, Cedar 

 Hill-on-Hudson, N. Y., and the Bowker Insecticide Co., Boston, 

 Mass., (Disparene) have all been used in our tests and have 

 given satisfaction. Arsenate of lead should be used in the 

 following proportions : — 



Formula i^"^"^'" °* ^"^^ 3-S lbs. 



(^ Water So gals. 



There are two methods of spraying elms: (i) To spray as 

 soon as the leaves unfold, the treatment being aimed especially 

 at the parent beetles, and to forestall all injury. As growth 

 takes place, new leaves are constantly appearing, and these will 

 not carry poison unless the application is from time to time 

 repeated. This should be done often enough to ' keep 

 the foliage well coated with poison until July 1st, when growth 

 usually ceases, and both sides of the leaves should be coated. 



(2) The other method is to spray the under sides of the 

 leaves very thoroughly about June ist, or soon after the eggs 

 begin to hatch. This treatment is aimed at the larvae, and 

 sometimes a single spraying is sufficient, as the poison will 

 remain throughout the season. By it the great bulk of damage 

 will be prevented, but the leaves will show the small holes made 

 by the parent beetles before the poison was applied. 



If arsenate of lead cannot be procured and it seems desirable 

 to use other poisons, Paris green can be substituted. 



This should be used at the following rate : 



Formula ■ 



Paris Green i lb. 



Fresh lime 3 lbs. 



Water 50 gals. 



Paris green is quicker in its action upon the insects than 

 arsenate of lead, but will not remain as long upon the trees. 

 Unless the lime is added, there is danger of "burning" the 

 leaves. Lime is not needed with arsenate of lead. 



The cost of spraying elm trees will vary from ten cents 

 each in case of small trees to five dollars or more for the largest 

 trees, according to the price of labor and the efficiency of the 

 outfit. 



