Carpet Beetle Management

MANAGEMENT
Carpet beetles are among the most difficult indoor pests to control because of their ability to find food in obscure places and to disperse widely throughout a building. Successful control depends on integrating the use of sanitation and exclusion, and, where necessary, insecticides.

When carpet beetles threaten products in commercial warehouses or storage areas, a monitoring program using sticky traps baited with an appropriate pheromone (a chemical attractant produced by an organism to attract others of the same species) is recommended. Traps placed throughout a building can show where beetles are coming from; the traps are also useful for monitoring the effectiveness of control applications. Check traps once or twice a week. Pheromone traps can also be used to augment other control methods when used to attract adult males in small, confined areas. Sticky traps are also available without a pheromone; these traps can be placed on window sills to trap adults that fly to windows. Plain sticky traps are available in retail stores; sticky traps with a pheromone can often be purchased from local pest control operators or from distributors of pesticide supplies.

Eliminate the Source
Eliminate accumulations of lint, hair, dead insects, and other debris that serve as food for carpet beetles. Throw out badly infested items. Remove bird, rodent, bee and wasp nests, and old spider webs, which may harbor infestations. Examine cut flowers for adult beetles.

Regular and thorough cleaning of rugs, draperies, upholstered furniture, closets, and other locations where carpet beetles congregate is an important preventive and control technique. Frequent, thorough vacuuming is an effective way of removing food sources as well as carpet beetle eggs, larvae, and adults. After vacuuming infested areas, dispose of the bag promptly because it may contain eggs, larvae, or adult insects.

Protect fabrics by keeping them clean: food and perspiration stains on fabrics attract carpet beetles. Dry cleaning or thoroughly laundering items in hot water kills all stages of these insects. This is the most common method used to control fabric pests in clothing, blankets, and other washable articles.

Mounted animal specimens, such as museum specimens or game trophies, should be regularly cleaned or periodically placed in a freezer for 10 to 14 days. Inspect stored woolens, linens, and furs; air, brush, and hang them in the light on a yearly basis. If infestations are found, launder or dry clean these items to destroy carpet beetle adults, larvae, and eggs before returning them to storage. Be sure cleaned items are sealed in a protective plastic bag or other suitable container.

Some furniture, mattresses, and pillows are stuffed with hair or feathers. When carpet beetles or clothes moths get into the stuffing, they cannot be controlled simply by spraying the outside surface of the item. The best way to eliminate them is to have the infested item treated with lethal gas in a fumigation vault. This service is provided by some pest control and storage firms. Because of the potential hazards to the applicator of the fumigant, only licensed pest control operators can buy and use them. Proper fumigation gives quick, satisfactory control, and kills all stages of fabric pests. It does not prevent reinfestation, however.

Protecting Items in Storage
To properly store items that are susceptible to carpet beetles, first make sure they are pest-free and clean. Place them in an airtight container, using paper to make a layer every few inches. On the layers you can place insecticide-impregnated resin strips that are labeled for control of carpet beetles on fabrics, or you can use moth balls, flakes, or crystals, which contain naphthalene or paradichlorobenzene (PDB). Do not place these materials in direct contact with plastic buttons, hangers, or garment bags as the plastic may soften and melt into the fabric. Also, be sure to keep these materials out of reach of children and pets; do not use them where unwrapped food is stored or allow them to come into contact with food or cooking utensils.

Generally, closets are not airtight and are opened too frequently to hold in vapors. However, seldom-used closets can be made into a suitable storage space by sealing cracks around the door with tape or fitting the door with weatherstripping. Seal cracks in walls and ceilings with putty or plastic wood. A trunk, chest, box, or garment bag makes a good storage container. Seal any holes or cracks. If the lid does not fit tightly, seal it with tape or wrap the entire container in heavy paper and seal it with tape.

Alternative methods of controlling dermestid beetles are either to freeze an infested object by placing it in a freezer (enclosed in a plastic bag) for 2 weeks at temperatures below 18°F or heating it in an oven for at least 30 minutes to temperatures above 120°F. (Before using either of these methods, consider if the object will be damaged by cold or heat.)

Questions are often raised as to the effectiveness of cedar chests and closet floors made of cedar. Some cedar contains an oil that does not affect large larvae but is able to kill small larvae. However, cedar loses this oil as it ages. Having the chest tightly constructed is more important in the long run than the type of wood used to make it.

Insecticides
Cleaning is always the best strategy; however, areas or articles that cannot be dry cleaned or laundered can be sprayed with an insecticide. Find a product that lists carpet beetles on its label and closely follow the directions. Apply insecticides as spot treatments and limit sprays to edges of floor coverings, under rugs and furniture, floors and walls of closets, shelving where susceptible fabrics are stored, cracks and crevices, and in other lint-accumulating areas. Be sure not to spray clothing and bedding.

When treating attics, wall voids, and other inaccessible places, use dust formulations. Do not let borates come in contact with objects containing natural dyes (e.g., some Oriental rugs, sheepskins, bearskins). Also, some dust formulations may adversely affect people with respiratory problems; read and follow label precautions carefully. Fumigation may be needed when infestations are extensive, although success can be limited by the ability of the fumigant to penetrate all the areas where carpet beetles hide.

On rugs and carpets, closely inspect areas beneath heavy furniture and along carpet edges for infestation. Spray both sides of infested carpet if at all possible. Apply a lighter spray to the upper surface so that the possibility of staining is reduced. If the rug pad contains animal hair or wool and has not been treated by the manufacturer, spray it also. It is preferable to wait until the rug has dried before putting any weight on it. If you are worried that expensive broadlooms or Oriental rugs may be damaged by sprays, employ an experienced pest control operator or carpet-cleaning firm.

Do not use insecticides around open flames, sparks, or electrical circuits. Do not spray them on asphalt or tile floors. Use only lightly on parquet floors. On linoleums, first spray a small inconspicuous area and let it dry to see if staining occurs.

Applying protective sprays to furs is not recommended. If you store furs at home throughout the summer, either protect them with moth crystals, flakes, or balls, or periodically shake and air them. Furs in commercial storage receive professional care and can be insured against damage.

Sometimes felts and hammers in pianos become infested and so badly damaged that the tone and action of the instrument are seriously affected. The services of a piano technician are then recommended. Synthetic felts are also available.

UC ANR Publication 7436