20 MffiSC. PUB. 5 2 6, U. S. DEPT. OF AGRICULTURE 



In situations where no domestic or farm animals have access to the 

 bait, apply it in piles of about a tablespoonf ul each, spaced about 2 feet 

 apart; otherwise it should be scattered in the infested area as recom- 

 mended for applying poisoned.-bran bait (p. 28) . Unless washed away 

 by watering or rains it remains effective for some time, and baiting two 

 or three times during the year gives adequate control. Ready-mixed 

 baits containing calcium arsenate and metaldehyde are available on the 

 market. 



Caution. — Since metaldehyde may cause poisoning when taken 

 internally, the containers should be plainly labeled "Poison" and 

 kept out of reach of children and others. 



METHYL BROMIDE 



Methyl bromide (CH 3 Br) at temperatures above 40° F. is a gas that 

 is heavier than air. Under pressure it becomes a heavy, colorless liquid 

 which is only slightly soluble in water. It is soluble in alcohol, chloro- 

 form, ether, and carbon disulfide. Commercially it has some use as a 

 fire extinguisher and as a refrigerant. The gas is noninflammable, 

 almost odorless, very penetrating, and is poisonous. As commercially 

 produced it has a purity of 99y 2 percent or better. 



For the destruction of insects and mites on plants and in soil methyl 

 bromide is being used as a fumigant in specially constructed chambers. 

 Under carefully controlled conditions of temperature, exposure, and 

 dosage it will destroy these pests without injury to the plants. In 

 this respect it is more useful as a general treatment than other fumi- 

 gants. 



Special fumigation chambers and special instructions are necessary 

 for its proper use. Information on these points can be furnished, to 

 those who have need for it, by the Bureau of Entomology and Plant 

 Quarantine. United States Department of Agriculture, Washington, 

 D. C. 



Caution. — When working with methyl bromide it is necessary 

 to use a gas mask provided with a canister that will absorb the 

 gas. It is toxic, and should not be allowed to come into contact 

 with the skin. Containers of this gas should be stored in a cool, 

 well-ventilated place outside of inhabited buildings. The gas is 

 practically odorless, but dangerous concentrations of it may be 

 readily detected by the use of a specially devised halide leak de- 

 tector or lamp. 



Methyl bromide is obtainable in small 1-pound cans or in cylinders 

 containing 10, 50, or 150 pounds net. 



MINERAL OIL 



Mineral oil, or petroleum oil, is obtained by refining native crude 

 oil. Refined petroleum oils used for controlling insects may be di- 

 vided into two general types known as dormant oils and summer oils, 

 the latter being highly refined products, also called white oils. 



Dormant oils. — Dormant oils having a viscosity of from 90 to 150 

 seconds (Saybolt, at 100° F.) and an unsulfonatable residue of from 

 50 to 70 percent are emulsified at the rate of 2 to 6 gallons per 100 

 gallons of water for the control of several fruit insects, such as the 



