THE ROUNDHEADED APPLE-TREE BORER, 19 
taining considerable quantities of benzine or turpentine can not be 
used on apple trees with safety.. Some persons have had good success 
from the use of fish-oil soaps and carbolic-acid washes, but in tests 
made by the Bureau of Entomology these have not proved to be of 
any benefit. 
| MECHANICAL PROTECTORS. 
Various mechanical protectors or coverings, to be placed around 
the lower portion of the trunk for the purpose of excluding the 
_ female beetle from the bark, have been devised. Wrappers made of 
newspapers are quite effective for this purpose. These wrappers, or 
any protectors of like nature, should be placed around the base of 
the trunks early in May, the season varying with the locality, and 
should cover the trunk from a foot or so above the ground to a short 
distance beneath the surface. The earth at the bottom should be 
mounded around ihe protector so as to leave no exposed portion of 
bark at that point. Building paper, cloth, cotton batting, fine- 
meshed wire screen, moss, and other materials may be used in the 
same way with success. Tarred paper has been recommended, but 
tests have shown that trees wrapped with it are likely to be injured 
thereby. 
Such devices as those just described should be tied at the top close 
to the body of the tree, preferably with a piece of twine, to pre- 
vent the beetles from crawling down to oviposit between the trunk 
and covering. These protectors have the disadvantage of furnish- 
ing breeding and harboring places for the woolly aphis, an insect 
destructive to apple trees, and for that reason they should be re- 
moved from the trees as soon as possible after the egg-laying season 
of the borer is past. It is probably safe to remove them in any 
locality by the 1st of September. Eggs will be deposited occasionally 
around the upper margins of the protectors, but the resultant borers 
are easily located and destroyed. It is doubtful if trees can be 
protected as economically with devices of this kind as with paint, 
and since paint of the proper kind is of almost or quite as much value 
in preventing attack, it may often be used in preference to the other 
form of covering. 
SPRAYING WITH ARSENICALS TO KILL ADULTS. 
As is stated on page 10, the borer in its adult stage feeds more or 
less on the exposed surface of leaves and twigs (fig. 16) and on 
the moisture contained in fresh castings thrown out by borers still 
working in the trees. The quantity of food taken in this way is 
sufficient to enable the beetles to be killed by spraying with arsenate 
