ELM LEAF BEETLE. 823 



Birds of various kinds are known to feed upon the beetles in 

 their larval, pupal and adult stages. Some of the creepers have 

 been observed apparently feeding upon the pupas. 



REMEDIES. 



spraying with poison. Covering the foliage with some arsenical 

 poison is the only sure means of preventing injury to the trees, 

 and for this purpose arsenate of lead is unquestionably the most 

 satisfactory of these poisons. It remains better in suspension and 

 adheres to the foliage longer than Paris ^reen or London purple, 

 and is less liable to injure it. As there are now several brands 

 of good arsenate of lead on the market, it will no longer pay 

 to make it up each time from lead acetate and arsenate of soda. 

 The standard brands of lead arsenate on the market are as a 

 rule satisfactory and many of them have been used in our tests. 

 If anyone desires to know the chemical composition of these pre- 

 parations he should consult Bulletin 157, or the Report for 1907, 

 p. 323, of this station, both of which give the analyses of most 

 of the brands which were sold on the market in 1907. Since thert 

 a few new brands have been added, some of which have been 

 examined here. It is fair to state that it is safe to purchase any 

 of them if made by well-known and reliable firms, though as the 

 published analyses show, there is considerable difference in the 

 value on account of the composition and each purchaser should 

 obtain guarantees and prices before buying in large quantities. 

 There are also certain differences in mechanical condition which 

 should be considered. Arsenate of lead should be used in the 

 following proportions : — 



T, , ( Arsenate of lead 3-5 lbs. 



Formula -j „, , 



( 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. This treatment 

 should be practiced wherever canker worms are destructive. 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 ist, when growth 

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



