THE BRONZE BIRCH BORER 77 



REMEDIAL SUGGESTIONS 



This bronze birch borer is practically invulnerable against man's usual 

 insecticides. Nearly all of its life is spent as a borer under the bark out of 

 reach of insecticides. The fact that the beetles feed for a few days on tender 

 leaves would suggest spraying the trees in May with a poison, but apparently 

 they do not eat the birch foliage to any extent, preferring that of willow, pop- 

 lar, or elm. Thus it is very doubtful if it would materially check the insect 

 to spray the birches with a poison. 



On account of the possibility that the beetles might be prevented from 

 emerging or from laying their eggs, several applications to the bark have been 

 suggested, such as a poisoned whitewash, a mixture of hydraulic cement and 

 skim milk, covering the trunks with a paper wrapping, and a resin-oil wash. 

 Adams treated about forty trees in Buffalo with a resin-oil wash (5 pounds 

 resin dissolved and i gallon raw linseed oil poured in) with no satisfactory 

 results. As the insect infests all parts of the tree, from branches half an 

 inch in diameter to the trunk, it would be difficult to so cover the bark 

 as to allow no place for egg-laying, or to put on such a coating as to prevent the 

 exit of the beetles. I doubt the practicability and effectiveness of such 

 methods against this birch borer. 



Some have tried to save their trees by cutting out the top branches that 

 were dead or dying, but in every case the trees finally succumbed. This 

 pruning may sometimes delay the inevitable death of the tree for a year or 

 more. / doubt if a tree can be saved after it is once infested to the extent that 

 the top branches are dying. Better sacrifice the whole tree at once and thus 

 prevent the spread of the pest to neighboring trees. 



This brings me to the only practicable and effective method of dealing 

 with this borer. That is the heroic one of cutting down and burning the 

 infested tree, trunk and branches, before May ist, thus destroying the whole 

 crop or generation of borers in their hibernating quarters under the bark. 

 As soon as the top branches are killed (as shown in the frontispiece and in 

 Fig- 34)) do not delay a moment, but cut and burn the tree, as its death is 

 inevitable within a year or two. 



But this is much more easily said than done, as any one can testify who 

 has tried to persuade owners of private grounds or park authorities to apply 

 the method in time. Sentiment and the forlorn hope that the tree may revive 

 or last a few years more, often results in an infested tree remaining as a leaf- 

 less eyesore on the landscape for a year or more after it is dead and all the 

 beetles have been allowed to emerge and spread to other trees. It seems to 

 be almost impossible in many cases to get individuals or city authorities to act 

 promptly. Often after one succeeds in getting an infested tree cut down in 

 time, it will not be burned promptly, but left where the beetles can readily 

 emerge, so that practically nothing is accomplished in checking the pest. 



A determined effort is' now being made to save the remaining white 



