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(CX) 2 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 y 8 to V4 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 1 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, page 33.) The 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 poison- 

 ous nature to humans and with the tolerance of different plants 

 to the gas. 



CARBON DISULFIDE 



Carbon disulfide (CS 2 ) is a heavy, colorless or faintly yellow liquid 

 which boils at 115° F. It has a disagreeable odor and is very volatile. 

 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 tablespoon!' uls 

 in 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. 



