CONTROL OF ARGENTINE ANT IN CALIFORNIA. 27 



1918, and has since been used on more than 2,000 acres of citrus. It 

 is of thin consistency and greater stability than Formuhi I. It has 

 proved very attractive to ants and has been highly effective in control 

 and eradication It was discovered, however, that fermentation of 

 this more dilute sirup sometimes occurred, especially in the damper 

 sections near the coast. This was corrected by the use of benzoate 

 of soda at the rate of 0.1 per cent. 



Preparation of final and most satisfactory formula. — The final form- 

 ula was prepared as follows: 



Cost. 



Water .■ 11 pints .SO. 000 



Tartaric acid' (crystallized ) 7 grams OIG 



Benzoate of soda .- 9 grams 029 



Granulated sugar 12 pounds 3.00 



Honey, strained 2 pounds 77 



Sodium arsenite, C. P | ounce 047 



Total sirup, 2J gallons. Cost per gallon, $1.54." 



Put 10 pints of water in a clean vessel over a low fire. WTien tepid add tartaric 

 acid, then benzoate of soda, and then the sugar, slowly, while stirring to j^revent 

 burning. Measure the depth of the liquid with a stick. (Slowly bring it to a boil 

 and allow it to simmer for from 30 to 40 minutes. Remove from the stove and add 

 water to compensate for evaporation. Stir in the honey before the mixture cools. 

 Then add sodium arsenite which has been dissolved in 1 pint of hot water and par- 

 tially cooled before being poured into the sirup. Stir thoroughly. 



It is necessary that great care be exercised in the selection of the 

 materials used, as well as in the preparation of the sirup. Either 

 cane or beet sugar may be used. The sodium arsenite should be 

 chemically pure. The honey should be strained and free of comb. 

 The sodium arsenite preferably should be dissolved in distilled water 

 to avoid the precipitation which sometimes ocQurs if very hard water 

 is used. • Vessels should be thoroughly cleaned before being used for 

 the preparation of ant sirup, and it is desirable that they be used for 

 this purpose only. Oils and various chemicals are distasteful or 

 repellent to ants, and sirup which acquires a flavor of such substances 

 from the container in which it is prepared or stored may be unattended 

 by the ants. The stability of the sirup depends much upon the way 

 it is boiled. If brought to a boil within a few minutes and boiled 

 vigorously for 30 minutes the stability appears to be much less than 

 if brought to a boil very slowly and then merely allowed to simmer 

 for 30 or 40 minutes. Where several times the amount given in the 

 formula is made in a large vessel the sirup appears to "stand up" 

 best. This seems due to the fact that the sirup does not come to a, 

 boil for an hour or longer, and this probably results in greater inver- 

 sion. The sirup should be used when fresh.* Clean glass bottles are 

 best if the sirup is to be stored. 



" With sugar at iireseiit prices (about lOceutsa pound) the cost would bo only about 82 cents a gallon. 



