26 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
2 inches from the trunk so as not to touch the bark, and then covered 
with a mound of earth. The earth mound and any remaining crystals 
should be removed in from 10 to 14 days. This treatment is snot very 
effective in cold weather. 
Preliminary work with some of the newer insecticides, such as ben- 
zene hexachloride, indicate that they may be very useful in borer 
control. 
SPECIAL TREATMENTS FOR CERTAIN BORERS 
The Locust Borer 
Control of the locust borer (Alegacyllene robiniae) through silvi- 
cultural practices is discussed on page 244. Occasionally it is desirable 
to utilize a spray on small plantations or individual trees for the con- 
trol of this insect. The most effective insecticide for this purpose is 
one of the fumigant sprays described in preceding paragraphs. 
The spray must be apphed early in the spring when the leaves are 
unfolding, before the borers go into the wood. The trunk of the 
tree should be given a complete covering, especially from the ground 
line to a height of 5 or 6 feet. The spray should not be applied to the 
young br anches or foliage, as there is danger of burning. 
The Ash Borer and the Elm Borer 
Injury to ash plantations by 7'y/onotus bimaculatus, the round- 
headed ash borer, and the elm borer (Saperda tridentata Oliv.) can be 
somewhat lessened by sanitation cuttings to remove heavily infested 
trees during the fall and winter. The stumps should be cut at least 
to the level of the ground, and preferably an inch or two below the 
ground line, since the base of the tree is frequently heavily infested. 
The infested material should be burned before the beetles emerge in 
the spring. In areas where green ash is especially susceptible to at- 
tack by this borer and by the carpenter worm, the ash trees should be 
planted only on the more favorable sites. 
The Poplar Borer 
Fast-growing trees are less attractive to the beetles than slow-grow- 
ing ones, and the tendency for the poplar borer (Saperda calcarata 
Say ) to concentrate its attacks upon trees already infested or weakened 
can be used to advantage to protect surrounding trees, by cutting and 
burning these so- called brood trees or by splitting the infested logs 
and exposing them to the direct rays of the sun. Coal-tar creosote 
painted over the egg scars soon after Ovafpoenaon is recommended for 
killing the eggs. I ‘umigating sprays (p. 25) can also be used. Caution 
should be exercised in handling eualt tar creosote, as it irritates 
the skin and eyes. 
The Carpenter Worm 
The carpenter worm is controlled in much the same manner as the 
poplar borer, or a few drops of carbon disulfide squirted into the 
galleries, followed by plugging the entrance with wet mud or putty, 
is effective against this insect. 
