CONTROL OF ARGENTINE ANT IN CALIFORNIA. 41 
Therefore an effort to eliminate the ant was immediately started, and 
on August 28 ant poison prepared according to the original Barber 
formula was placed in paraffined paper bags on a 2-acre demonstra- 
tion orchard, a bag to each tree. Within two weeks the effectiveness 
of the sirup was apparent, a reduction of fully 50 per cent being shown 
over the adjacent untreated trees. Within a month the ants were 
under control on most of the trees. 
This very successful demonstration proved immediately convinc- 
ing to orchardists in the neighborhood, and by the months of Sep- 
tember and October the owners, representing 160 acres of infested 
orchards, had been induced to attempt ant control. During 1918 the 
territory covered was greatly extended and by the end of the year the 
treated territory had been brought up to 490 acres, or only 110 short 
of the entire mealybug-infested territory. These 110 acres were 
placed under control during the spring of 1919. 
The methods which have been put into operation by the writers 
and are fully presented under demonstration orchard B were applied 
throughout the campaign. The original Barber poisoned sirup was 
used during 1917, but in 1918 the modified more dilute sirup was 
adopted and subsequently used exclusively. A very large amount 
of the poisoned sirup was prepared under the direction of the junior 
author or was supplied by qualified druggists. Spice tins were used 
very largely as containers. 
The results of these very extensive control operations were entirely 
satisfactory. Total eradication of ants over a large acreage was 
accomplished during 1918. In the spring of 1919 a careful inspection 
was made of all the acreage on which control had been attempted, 
the results of which are shown in figure 21. At that time the ants 
had been entirely eradicated over approximately 450 acres, including 
the territory over which control was started in 1917. The entire 
area was under control by the spring of 1920. 
The cost of control for the whole district averaged between 4 and 
5 cents per tree. 
SUMMARY. 
An investigation of methods for control and eradication of the 
Argentine ant was started in 1915 and continued until 1920. The 
methods used included banding of trunks to prevent the access of 
the ant, trap nesting, repellents, and the use of poisoned sirup. 
Of the various substances tried in banding, a mixture composed of 
1 part of sulphur and 6 parts of commercial sticky tree-banding 
material proved most satisfactory. The careful attention necessary 
to keep the bands in a freshened condition, their high cost, and the 
ourstanding fact that the ants remained an everlasting menace, 
however, led to their discontinuance. 
