42 



Whether this control is a permanent one, or whether, under favorable 

 conditions the insects will again become injurious, it is impossible to 

 say. At all events it is advisable for those who have charge of elm 

 trees to watch this beetle closely, and if at any time the number found 

 feeding in early spring is sufficient to make it probable that injury 

 will be caused, prompt action should be taken. 



Remedial Measures. 



As this insect is a feeder upon leaf tissue, arsenites are indicated, 

 and, as a matter of fact, have proved themselves effective. Paris 

 green has been most generally employed and, at the rate of one pound 

 in one hundred and fifty gallons of water, forms a satisfactory remedy. 

 Arsenate of lead, at the rate of one pound in seventy to seventy-five 

 gallons of water, has also been used to good advantage and is prefer- 

 able because of its greater lasting qualities. In any ease where the 

 insect is to be dealt with by insecticides, a spraying should be made 

 as soon as the first feeding by the adults is noticed. This spraying 

 is very important, because, if the beetles can be killed off before they 

 lay eggs, there will be no larvae to deal with later. As both sexes 

 hibernate and the ova develop after the beetles have begun to feed, 

 there is a period of a week or ten days during which they may be 

 reached before egg-laying begins. Where only a few trees are to be 

 looked after, a second spraying, made about a week after the first, is 

 desirable. The reason is that the foliage at that period develops so 

 fast that a week after the treatment there will be an abundance of 

 new leaves upon which the beetles may feed safely. If it becomes 

 necessary to deal with the larvae, spraying may be delayed until hatch- 

 ing from the eggs is quite general; then the application should be 

 made very thoroughly, and it is now important to reach the under- 

 sides of the leaves, rather than the upper. The beetles eat the entire 

 leaf tissue and it makes no difference whether the poison is on the 

 upper or on the under surface. The. larvae eat only the lower layer of 

 cells, and, even if the upper surface be fully covered by the arsenical 

 poison, they may not get even a particle. It should be emphasized, 

 then, that whenever a spraying is .made, having for its object the 

 destruction of the larvae, ^very effort sliould be made to reach the 

 under side of the foliage. It is the neglect of this point that has 

 resulted in the lack of satisfactory results in many cases. 



