626 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
dearth of other green foliage. In longleaf pine the needles are cut 
off close to the bud of the seedling, and in slash pine both the needles 
and bud are cut off and the living bark is girdled. The injured long- 
leaf pines are weakened, but the damage resulting from defoliation 
is not severe unless drought or other factors affect ‘the tree. In slash 
pine the injury kills the trees. After trees have become 2 or 3 feet 
high, they seem to have grown beyond the stage of fatal injury. 
Another type of injury is that to longleaf seedlings i in the cotyledon 
stage under natural reproduction, where total loss has been caused in 
areas immediately adjacent to the ant colonies. 
Colonies can be controlled and, if treated thoroughly at the proper 
time of year, can usually be eradicated with carbon disulfide. The 
best kill is obtained from late in February until early in April, when 
the ground is warm enough for rapid evaporation of the chemical and 
the ants are concentrated in the nest. In nests treated during the 
summer the number of ants is reduced appreciably, but only a small 
percentage of the colonies are eradicated. Success of the treatment 
with carbon disulfide depends on keeping the chemical in, and the fresh 
air out of, the passages into the nest. Approximately 2 ounces of 
carbon disulfide should be poured into one or two holes within each 
10-foot square of the nest area, and all passages, both treated and un- 
treated, should be stamped shut. The easiest way to pour the chemi- 
cal into the holes is by means of a 5-foot section of 14-inch rubber 
tubing attached to a small funnel. Insert the tube deep down into 
the passages (by a twisting push) before the chemical is poured in. 
(See caution on p. 23.) In ‘the Kisatchie National Forest 178 colonies 
were located and treated during the winter of 1936-37 in fenced areas 
that aggregated 18,799 acres. The colonies averaged 300 holes each— 
an average of 74 of which were treated. To treat adequately an 
average colony required 7.2 pints of the chemical. 
Johnston (259) showed that methyl bromide was effective and prac- 
tical for control of the Texas leaf-cutting ant and that its use has many 
advantages over the use of carbon disulfide. In the winter or early 
in the spring 1 pound of methyl bromide should be released through 
a piece of rubber tubing attached to the applicator about 2 feet down 
in the tunnels in the central part of the colony. This treatment will 
eradicate or greatly reduce a colony of average size. It is unnecessary 
to close the entrance tunnels to the colony at the time of application. 
The Allegheny mound ant (Formica exsectoides Forel) 1s common 
throughout the East, and its large mounds, or nests, often 3 feet high 
and 6 feet in diameter, are frequently seen in wooded areas. The 
ants in these mounds may destroy almost all the vegetation around 
the nests for a distance of 20 feet or more, although large trees are 
rarely affected. The chief damage is done to young trees in planta- 
tions or clearings. White pine from 2 to 15 years old, red pine, Scotch 
pine, red cedar, spruce, and many other species are killed. The ants, 
however, are not vegetarians. They feed on a wide variety of insects, 
both living and dead, but their principal food is the honeydew given 
forth by insects that suck sap from trees. Peirson (349) showed that 
the trees are killed by an injection of formic acid into the tissues of 
the main stem a short distance above the ground. The acid coagulates 
the cell contents, thus preventing the downward flow of sap. The 
