22 BULLETIN 965, V. S. DEPARTMENT OF AGRICULTUEE. 



.ORIGINAL BARBER FORMULA. 



Orchard A. The owner of a 10-acre orchard of large Valencia and 

 naval orange 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 

 w^rk was done under contract and the poison prepared according to 

 the original Barber formula as follows: 



Granulated sugar ; pounds. . 15 



Tartaric acid (crystallized) , ounce. . . i 



Sodium arsenite C. P do f 



Honey pounds. . IJ 



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 14-15, 1917. No inspection was 

 made at the time of sirup distribution, although during the previous 

 autunm 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 dfter 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, mth 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 D8 per cent 



