48 CIRCULAR 3 6 9, U. S. DEPARTMENT OF AGRICULTURE 



tive. A dosage of 20 pounds per 1,000 cubic feet of space and an 

 exposure of 24 hours at a temperature of 70° F. or higher will give 

 satisfactory results. 



In packing houses or storage sections where fumigation chambers 

 or fumigable storage bins are not isolated, a fumigant that does not 

 have the fire hazard of carbon disulfide is desirable. In such cir- 

 cumstances any of the following materials can be used at the dosages 

 indicated per 1,000 cubic feet: Ethylene oxide, 2 pounds; ethylene 

 oxide-carbon dioxide mixture, 20 pounds ; methyl formate-carbon di- 

 oxide mixtures, 30 pounds ; methyl bromide, 1 pound ; chloropicrin, 1 

 pound ; ethylene dichloride-carbon tetrachloride mixture, 20 pounds ; 

 or liquid hydrocyanic acid or its equivalent, 20 ounces. Hydrocyanic 

 acid gas is absorbed in considerable quantities by dried fruit, but it is 

 ordinarily quickly given off after the fruit is aerated. 



TREATING THE FINISHED PRODUCT 



It is sometimes desirable to fumigate the finished package before 

 it is shipped. For this purpose a fumigation room or a vacuum tank 

 is necessary. If a fumigation chamber is used, the fumigants and 

 dosages recommended for the raw products can be used. If vacuum 

 fumigation is resorted to, excellent results can be obtained with a 

 dosage of 30 pounds of the ethylene oxide-carbon dioxide mixture per 

 1,000 cubic feet for a period of from 1 to 2 hours. 



Carbon disulfide blanketed with carbon dioxide is frequently used 

 for this purpose. Individual packages can be successfully treated in 

 the packing line with methyl formate. From 5 to 9 cubic centimeters 

 of this material is spattered into the bottom of the paper or paper- 

 bag liner of 25-pound boxes of dried fruit. The fruit is then dropped 

 into the box, the liner folded over, and the cover nailed or pasted 

 down. 



INFESTATIONS IN WAREHOUSES 



Infestations that develop in storage warehouses can be handled by 

 fumigating the infested fruit in a fumigation chamber or vacuum 

 tank or by fumigating the entire storage section with hydrocyanic 

 acid. If the entire storage section is fumigated, a dosage of from 

 8 to 20 ounces of liquid hydrocyanic acid or its equivalent per 1,000 

 cubic feet of space should be used for a period of 24 hours. The 

 dosage will depend on the tightness of the storage section and the 

 quantity of fruit in storage. 7 



Cured Meats and Cheeses 



Infestation of cured meats and cheeses by mites, ham beetles, or 

 skippers frequently makes fumigation necessary. Meat-storage houses 

 that are reasonably tight can usually be successfully fumigated with 

 hydrocyanic acid at the rate of 1 pound of liquid hydrocyanic acid 

 or its equivalent per 1,000 cubic feet for a period of 24 hours. Such 

 treatment does not injure the meats, but if the infestation has pene- 

 trated deeply into the meat, it is difficult to get a perfect kill. The 



7 Detailed information regarding the fumigation of dried fruit can be found in the 

 U. S. Bureau of Entomology and Plant Quarantine Mimeographed Circular E-353, Dried 

 Fruit Fumigation. 



