INDUSTRIAL FUMIGATION AGAINST INSECTS 59 



and the following dosages are recommended per ton of rice with a 

 vault one-half full or more : Liquid hydrocyanic acid, 2 ounces for 3 

 hours ; methyl bromide, 3 ounces for 2 hours or 1% ounces for 3 hours ; 

 and ethylene oxide-carbon dioxide mixture, 2y 2 pounds for 1 hour or 

 iy 2 pounds for 3 hours. These dosages should be used with an initial 

 absolute pressure of 2 inches, and the f umigant should be circulated in 

 the vault for 15 minutes. If the vacuum vault is not equipped for 

 circulating the gas, the dosages should be increased by one-third. 



Cottonseed Meal 



Cottonseed meal, stored in 100-pound sacks, if held in certain 

 storages during the summer following grinding, may become seriously 

 infested with the cigarette beetle (Lasioderma serricorne) . The infes- 

 tation by this insect in commercially valuable meal is limited chiefly 

 to the outer 2 or 3 inches, whether it is stored in sacks or in bulk. If 

 market conditions indicate that the meal will be carried over the sum- 

 mer, losses resulting from rebates, regrinding, and resacking can be 

 prevented by fumigation. If insects are already very abundant in 

 meal stored in reasonably tight warehouses, one thorough fumigation 

 with hydrocyanic acid gas, at the rate of 1 pound of sodium cyanide 

 or its equivalent per 1,000 cubic feet of space, will kill from 95 to 97 

 percent of the insects. The small percentage escaping this treatment, 

 however, may represent so many in numbers that a second fumigation 

 3 or 4 weeks later with one-half pound of sodium cyanide per 1,000 

 cubic feet will be desirable. One fumigation, conducted when the cig- 

 arette bettles are first noticed, will usually give a practical control for 

 the summer and fall months provided there is no reinfestation from 

 flying beetles from neighboring meal storages. An early treatment 

 prevents destruction of the sacks, and the cost of labor and new sacks 

 in repacking. The above-mentioned dosages are based on experi- 

 mental fumigations. They are sufficient only for practical control 

 and not for complete eradication. 



SAFEGUARDS TO BE EMPLOYED IN FUMIGATION WORK 



In all fumigation work the person in charge should not only acquaint 

 himself with the dangers involved, but should bring his assistants 

 together and explain to them the need for caution, and what should 

 be done in case difficulty arises. He should know the first-aid recom- 

 mendations issued by the manufacturers of the particular fumigant 

 he is about to use. He should employ only men known to be depend- 

 able. Members of the fumigating crew should be in good physical 

 condition, with minds alert so that they can act calmly and rapidly 

 and work together according to a prepared and rehearsed plan of pro- 

 cedure. They should abstain from the use of intoxicants. They should 

 take no chances. 



All persons except fumigators should leave the building. 

 When an entire building, or any floor, is to be fumigated, all persons 

 in the entire building should be notified in advance and told that they 

 must leave the building between certain specified hours. In large 

 establishments the owners should be held responsible for keeping per- 

 sons out of a building unless they have a definite agreement with the 



