CONTROL OF ARGENTINE ANT IN CALIFORNIA. 
17 
large trees support aerial colonies during the warm season and not 
infrequently colonies have been noted in midwinter. 
Several methods of freeing banded trees were tried. The first 
method was to spray the trunk and main branches with such insect- 
icides as carbolic-acid emulsion or distillate emulsion immediately 
after banding, the application being made with a compressed-air 
pump holding 3 gallons. This proved too slow and ineffective, as 
ants are actively engaged throughout the tree during the day. It 
was soon observed that the early morning was the proper time to 
Fig. 7.— Plumber's torch for applying certain sprays to rid a banded 
tree of ants. 
destroy the ants above the bands, for they are sluggish at the cool 
temperatures and have the habit of congregating in crotches or in 
their aerial nests. The compressed-air pump was soon discarded 
in favor of a plumber's hand torch (fig. 7) , in which gasoline or a weak 
cyanid solution was used as a spray. This in turn gave way to the 
use of pyrethrum or other ant powders which proved simple of appli- 
cation, economical, and immediately effective. Nests in tree crotches 
or elsewhere could be quickly freed by a single application, and for 
this purpose either a small bellows or shaker (fig. 6) proved satis- 
factory. 
48155°— 21— Bull. 965 3 
