CONTEOL OF AKGENTINE ANT IX CALIFOENIA. 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 iuWy 50 per cent being showTi 

 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. 



