INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 9 
many kinds of insect pests. The gas is colorless, lighter than air, and 
has an odor resembling that of peach kernels or crushed almonds. A 
granular product containing about 42 percent of Ca(CN), is used for 
fumigation, especially in greenhouses, where the material is sprinkled 
on the walks or soil at dusk after the ventilators have been closed. 
It is used against greenhouse pests, such as aphids, the Mexican mealy- 
bug, whiteflies, and the broad mite, at low dosages of 14 to 14 ounce 
per 1,000 cubic feet of air space, preferably at temperatures of 60° 
to 75° F. At higher dosages, thrips, scale insects, mealybugs in gen- 
eral, and various bulb pests are also destroyed. Plants vary consid- 
erably in their tolerance to the gas, and the margin of safety between 
a fatal dose for an insect and a plant is very narrow, therefore it must 
be used with care. 
Calcium cyanide is used as a fumigant for the control of thrips 
and mealybugs on gladiolus corms, at the rate of 5 ounces per 1,000 
cubic feet of space with an exposure of 2 hours. The corms should 
be warmed to at least 60° F. just prior to the fumigation and held at 
that temperature during the fumigation. 
Colonies of ants in the ground may be controlled by dusting powdered 
calcium cyanide into their nests or pouring a teaspoonful into each 
_ of several holes about an inch in diameter, made with any convenient . 
instrument, about 6 inches deep and spaced i foot apart. Openings of 
the holes should be closed, but treated areas should not be covered with 
papers, since the poisonous hydrocyanic acid gas may injure the grass 
or other vegetation. 
Caution.—Hydrocyanic acid gas, from whatever source derived, 
is very poisonous to all animals and plants. (See also Sodium 
Cyanide, p. 33.) Therefore the calcium cyanide dust should be 
kept in tight containers, labeled plainly, and stored in a dry, safe 
place. This fumigant should be used only by those thoroughly 
familiar with its poisonous nature to humans and with the 
tolerance of different plants to the gas. 
CARBON DISULFIDE 
Carbon disulfide (CS,) is a heavy, colorless or faintly yellow liquid. 
It has a disagreeable odor and is very volatile, the boiling point being 
only 115° F. The vapors are poisonous and very inflammable, and are 
explosive when mixed with air in certain proportions. They will 
sometimes become ignited from contact with hot steam pipes. 
Carbon disulfide is used as a soil fumigant or as an emulsion against 
grubs of the Japanese beetle, white grubs, wireworms, and colonies 
of ants in the ground. To control ants in lawns, make holes about 3 
inches deep in the soil with an iron bar or sharpened stick, spacing 
the holes about 1 foot apart throughout the entire infested area. Into 
each hole pour 1 teaspoonful of carbon disulfide, then close the opening 
by pressing the earth in place with the heel. Where the ant nests 
occur in ground between stones of a walk, apply 1 or 2 tablespoonfuls 
im each hole. Carbon disulfide cannot be used safely near growing 
plants. 
Ant nests in trees may be destroyed by injecting carbon disulfide into 
openings to the galleries with an oil can and then plugging the open- 
ings with moist clay. 
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