22 BULLETIN 965, U. S. DEPAETMEXT OF AGEICrXTrEE. 
ORIGINAL BARBER FORMULA. 
Orchard A. The owner of a 10-acre orchard of large Valencia and 
navalorange trees located at Alhambra in a district overrun with the 
Argentine ant was induced to attempt control by the use" of the 
poisoned sirup which, had proved so successful in Louisiana. This 
work was done under contract and the poison prepared according to 
the original Barber formula as follows: 
Granulated sugar pounds . . 15 
Tartaric acid (crystallized i ounce. . . J 
Sodium, arsenite C. P do f 
Honey. pounds . . 1* 
Water pints . . 8 
A special 1-pound paraffined paper sack punched with a few small 
holes and containing about an ounce of sirup and a 1-inch cube of 
sponge was attached to each tree, either on the trunk or one of the 
main branches. The orchard was in a state of clean cultivation with 
no grass or weeds beneath the trees, and in most cases the lower 
limbs were entirely free of the ground, so that the trunk formed the 
only means of access to the tree for the ants. The distribution of 
filled containers was made on May 1-1-15. 1917. No inspection was 
made at the time of sirup distribution, although during the previous 
autumn trails of ants were present on every tree, and a careful exami- 
nation in April showed heavy streams of ants on trees in all parts of 
the orchard. 
Some of the paper bags lost their contents soon after distribution 
and these were replaced in the latter part of June. The sirup thick- 
ened rapidly during the summer and by the first of August, or proba- 
bly two months after the experiment was started, the contents of 
many bags had commenced to crystallize or solidify. When this 
stage was reached, it was noted that the sirup no longer proved so 
attractive to ants. A few bags were refilled in August, and in 
September fresh sirup was placed in all containers. 
After the sirup was distributed frequent inspections of this orchard 
were made throughout the season of ant activity and notes taken on 
the progress of the control and eradication. These results were 
most encouraging and showed conclusively not only that orchard 
control of the ant was possible, but that the ant could be eradicated 
by persistent effort. 
The experiment began on May 14. with most of the trees in the 
orchard heavily attended by trails of ants: by May 22. or within a 
week's time, these had been reduced to only 26 per cent with trails: 
and within two weeks to 11 per cent. By July 19. or two months 
after the poison was distributed, the ants had either been entirely 
destroyed or reduced to within the limits of control on 98 per cent 
