One of the safest methods of preventing loss through carpet-beetle attack is to store susceptible articles with a reliable cold-storage firm maintaining rooms for such purposes at a temperature of 50° F. or lower.
Carpet beetles, as well as all other household pests, can be eliminated as disturbing factors by fumigation within as short a time as three or four hours (if necessary). Fumigation with formaldehyde candles, although excellent for killing disease germs, is worthless for insect control, and the public is warned accordingly. Sulphur fumes will kill many carpet beetles, but very few persons succeed in killing all carpet beetles with sulphur fumes. Sulphur should be burned at the rate of 13½ ounces per 1,000 cubic feet of space. It is likely to bleach wall paper and fine fabrics and tarnish metals, and should never be used unless one is aware of these possible bad results.
Hydrocyanic-acid gas.—Hydrocyanic-acid gas is the best gas known and in present use for the fumigation of houses, or parts of houses, for the speedy elimination of carpet beetles or other pests. When persons are troubled with fabric pests that have become generally established throughout the house, nothing will give greater satisfaction in peace of mind and freedom from trouble than one thorough fumigation carried on by a professional fumigator or by any intelligent, careful person capable of following directions. Hydrocyanic-acid gas is dangerous to human beings, but is noninflammable and nonexplosive as used in household fumigation as here advocated. It is lighter than air, will injure no fabric or painting, and will not tarnish household metals. If properly used, it is one of the simplest and best methods of fighting house pests. Interested persons can have full particulars free of cost by writing the Division of Publications, Department of Agriculture, for Farmers' Bulletin 699.
Carbon disulphid.—Carbon disulphid is a fumigant in general use for killing insects of all sorts in containers that are reasonably tight. It is excellent for killing carpet beetles in chests, trunks, and closets that can be closed and sealed. It has been used for the fumigation of entire buildings when these are detached. It is purchased at drug stores or of chemical firms as a liquid put up in tin cans containing 1, 2, 5, or 10 pounds each. Upon exposure to the air, the liquid evaporates, forming a gas heavier than air which sinks through the container being fumigated and kills the insects by suffocation. The gas is explosive in the presence of fire, and must be handled with the same care as gasoline or benzine. Although the liquid as purchased is considered not explosive or inflammable, great care should be exercised in storing and handling it since it is almost impossible to dissociate it from its gas, which is, as stated above, decidedly explosive and inflammable in the presence of fire. The odor of carbon disulphid gas is very disagreeable, but soon disappears with the airing of the container after fumigation. Carbon disulphid fumigation is excellent for the destruction of carpet beetles in articles that can be stored in trunks, chests, or closets, or for killing pests in pianos and upholstered furniture that can be placed in a small room for the period of fumigation. Full particulars regarding this fumigant and the ease with which it can be used may be had by writing the Division of Publications, Department of Agriculture, for Farmers' Bulletin 799.
Carbon tetrachlorid.—Carbon tetrachlorid is used in exactly the same way and for the same purpose as carbon disulphid, except that from two to three times as much of the liquid must be used to fumigate the same amount of space. Carbon tetrachlorid is not a particularly effective fumigant, but it has the advantage of producing, upon evaporation, a gas that is noninflammable and nonexplosive, and for this reason can be used in certain places where lighted lamps, fires, etc., can not be entirely eliminated. See Farmers' Bulletin 799 for reference to use of carbon tetrachlorid and carbon disulphid.
MISCELLANEOUS CONTROL MEASURES.
Laundering and dry cleaning.—When material infested with carpet beetles is submerged in a solution of 1 pound of neutral soap to 10 gallons of water all stages of the beetles are killed. Carpet-beetle larvæ are killed if subjected to temperatures of 120, 125, and 128° F. for 30, 15, and 10 minutes, respectively. Eggs are killed when subjected to temperatures of 125 and 130° F. for 16 and 11 minutes, respectively Eggs and larvæ were killed in material dipped for 5 second in water at 140° F., but submergence for the same period in water at a temperature of 122° F. failed to kill all of them. Translated into household terms this means that laundering clothing or other textiles in thick suds or with water hotter than the hand can bear, or pressing with a hot iron, will probably kill the larvæ and eggs of the carpet beetle. The usual commercial dry-cleaning processes also are probably effective. Unfortunately these methods are not always easily applied to the articles most likely to be infested; they must not be considered a preventive against reinfestation.