1910.] PUBLIC DOCUMENT — No. 31. 71 



lowing winter — that of 1003-04 — was exceptionally cold, and 

 in llie spring of 190-4 almost no elm-leaf beetles conld be found. 



How far the unusually cold winter was responsible for this 

 destruction it is impossible to say, but it seems certain that the 

 spring drought, causing the failure of eggs to hatch, and the 

 starvation of the newly hatched young, were important factors 

 in the destruction of this pest. 



]\rany towns and cities sprayed their trees for the elm-leaf 

 beetle in 1903, and it seems to have been too generally supposed 

 that this was the reason so few of these insects were found the 

 following year. 



Since 1904 the elm-leaf beetle has been gradually increasing 

 in abundance again, and in 1908 it had become so plenty as to 

 cause considerable injury. In 1909 this was also the case, and 

 a repetition of this may be expected each year hereafter, until 

 some combination of natural or climatic conditions unfavorable 

 to the insect shall appear. 



The question of controlling the elm-leaf beetle is important 

 under these circumstances, and two lines of action seem possible. 

 Cities and towns may spray their trees if they see fit to do so, 

 holding the insect in check in this way. There are many parts 

 of the State, particularly on the west and north, as far east as 

 Ashby, perhaps, where it is not jirobable that this insect will 

 ever do serious injury, unless it acquires greater resistance to 

 cold than it now has. For this reason local treatment would 

 seem particularly desirable. The difficulty would be that trees 

 not on town streets, but on private grounds, and those in the 

 fields and woods w^ould not be reached in this way, and each 

 year these would restock the street trees. The other method 

 would be by State law requiring all elms to be sprayed. This 

 would be impracticable of enforcement, however, for there are 

 not enough people in the business to spray one one-hundredth of 

 the trees, and it is impossible to spray elms without power 

 sprayers, Avith any degree of success, during the period when 

 spraying must be done. If the State should take up the work, 

 it would mean the expenditure of about half a million of dollars 

 annually, for the entire State, except the western and north- 

 western portions, would need to be treated during a period of 

 five weeks for it to be of any value, and this would require at 



