THE DAVEY INSTITUTE OF TREE SURGERY 
and linemen in laying foundations or pavements, and in stringing 
telephone wires through the streets. 
CONTROL 
16. Although the borers do a great amount of injury to our 
trees each year, very little thorough work has been done to deter- 
mine satisfactory methods for their control. The problem is so 
dificult, and the prospect of obtaining satisfactory results is so 
small, that few entomologists have been tempted to undertake 
the work. It is much easier to guess at the remedy, to advise a 
remedy used for a similar insect, or to shift the responsibility alto- 
gether and follow the recommendations of the earlier writers. 
17. To judge correctly the value of the methods of control 
generally in use today, it is necessary to trace these methods back 
through the literature and see whether they are based upon care- 
ful observations or experiments, or simply given first as a guess 
and later quoted as a fact. 
18. The following quotations of remedies suggested for the 
control of the elm borer will serve as an illustration of the develop- ‘ 
ment of some of the remedies still in use: 
19. 1905, Felt. “The badly infested portion should be cut 
away and the grubs destroyed, and where a few are working in 
living bark it might be well to remove the upper layers till the 
grubs are nearly exposed, and then brush over the shaven surface 
with strong kerosene emulsion or whale-oil soap solution, finally 
covering the wound with a paste formed of a mixture of fresh cow- 
dung and lime.” 
20. 1893, Lintner. ‘‘Remove the outer bark from the entire 
infested portion of the tree in the spring by shaving it down to 
the inner bark until the first indications of the fresh burrows are 
disclosed. A kerosene emulsion of good strength brushed over the 
shaven surface would kill the insects, after which a coating of 
some thick substance, as lime and cow-dung, should be applied to 
prevent the splitting of the sap-wood from exposure to the sun, 
drying winds or extreme weather.” 
21. 1880. The use of kerosene emulsion as an insecticide was 
discovered about 1880 by the United States Department of Agri- 
culture, consequently is a recent addition to the remedies. 
22. 1848. Robert (France). “Strips about two inches wide 
were cut out of the bark from the large boughs down the trunk to 
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