70 BULLETIN 647, L T . S. DEPARTMENT OF AGRICULTURE. 



Method and Cost of Fumigating Ant Teaps. 



It is recommended that not less than 25 traps per acre of 100 trees 

 be used in ant trapping in the orange groves. There should also be 

 12 covers for each 100 traps. A trap should be placed near every 

 other tree each way. For example, one near each of the first, third, 

 and fifth trees in the first row, then similarly in the third, fifth, 

 and seventh rows. etc. The traps should be located just under the 

 outer spread of the trees, where they will not be in the way of the 

 cultivator or so close to the tree that the latter will be injured by 

 the fumigant. The distance from the trunk should be about 4 feet. 

 They should be placed upon slight, level elevations made by throw- 

 ing up and smoothing off a few shovelfuls of dirt. 



The ants will be destroyed much faster if every part of the 

 orchard, including ditch banks and the tree hills, is kept free from 

 weeds, loose boards, boxes, sacks, etc. It is, of course, not recom- 

 mended to plow and cultivate during the winter months, but the 

 orchard should be kept clean during the summer. In winter the 

 traps should be filled with damp but not wet stable manure and dry 

 weeds, the manure occupying the lower half of the box. In summer 

 the manure, which is used principally for its heat, may be omitted. 

 It is important to keep the lids on the traps at all times, as they 

 keep out the rain, a very essential condition, darken the nest, and in 

 winter help to retain its warmth. 



When the trap is full of ants and ready to fumigate the lid is 

 thrown off, 2 fluid ounces of carbon disulphid poured in, and the 

 cover quickly slipped on. the edges being banked with dirt to aid 

 in retaining the gas. One man can do the work where the number 

 of traps is small. "Where the number of traps is larger they can be 

 fiunigated most efficiently by a crew of three men, one of whom 

 measures and pours the liquid while the others remove the covers 

 from fumigated traps, place them over those to be fumigated, and 

 bank them with earth. A shovelful of soil tamped down at each 

 side is sufficient. The traps must be allowed to fumigate for an 

 hour. A crew of three men working continuously can handle 48 

 covers, removing them from one lot of traps and resetting them over 

 the next in from 50 minutes to an hour. Two ounces of carbon di- 

 sulphid will kill every ant in the trap and ants, worms, and sow- 

 bugs for 3 inches in the ground beneath. While the same trap filler 

 may be used indefinitely, it and the traps should be given a thorough 

 airing after each fumigation. 



The figures here given on the cost of installing and operating the 

 traps are based entirely upon the foregoing experiment conducted 

 by the Bureau of Entomology. The cost of the traps, made of 

 C-grade sap pine, all parts cut to fit, knocked down, was $0.23 each, 



