70 BULLETIN 647, U. S. DEPARTMENT OF AGRICULTURE. 
Method and Cost of Fumigating Ant Traps. 
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 
fumigated 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, 
