Carpet Beetles and Their Control

Part 1

Produced by Tom Cosmas compiled from images made available by The Internet Archive.

Transcriber Notes

Text emphasis denoted by Italics amd =Bold=.

U. S. DEPARTMENT OF AGRICULTURE

FARMERS' BULLETIN No. 1346

CARPET BEETLES AND THEIR CONTROL

CARPET BEETLES, or so-called "buffalo moths," are common household pests usually associated in their destructive work with clothes moths. Ordinarily they are not so destructive as clothes moths, because they reproduce only once a year, and then not so abundantly.

Experienced housewives throughout the North are familiar with the stout, oval, reddish-brown, hairy grubs or larvæ of the common carpet beetle, found beneath carpets or in clothing. In southern homes, however, the longer, slender, golden-brown larva of the black carpet beetle, with its tuft of golden bristles, is more common.

All carpet-beetle larvæ feed upon fabrics or upon various articles, including upholstered furniture, containing wool, silk, hair, fur, bristles, or feathers. They even feed upon dried animal matter.

Protection against carpet beetles can be secured in tight chests and trunks by the use of the crystals of naphthalene, paradichlorobenzene, or camphor, or by the fumigants carbon disulphid and carbon tetrachloride Where infestation is general throughout a house or is serious in closets, it may be advisable to fumigate with hydrocyanic-acid gas, carbon disulphid, or sulphur, but none of these fumigation methods should be employed except by a person well informed regarding them. The foregoing remedies and others, such as cold storage, red-cedar chests, heat, and the treatment of infested floor cracks, are discussed in this bulletin.

Washington, D. C.

July, 1923

CARPET BEETLES AND THEIR CONTROL.

By E. A. Back, Entomologist in Charge of Stored-Product Insect Investigations, Bureau of Entomology.

CONTENTS.

Page.

Carpet beetles or "buffalo moths" 1 The common carpet beetle 2 The black carpet beetle 4 The varied carpet beetle 6 The furniture carpet beetle 7 Control measures 9 Naphthalene 10

Page.

Control measures--Continued. Paradichlorobenzene 10 Camphor 10 Red-cedar chests 11 Cold storage 11 Fumigation 11 Miscellaneous control measures 12

CARPET BEETLES OR "BUFFALO MOTHS."

THE so-called "buffalo moths" are not moths; they are beetles and very distinct from the true clothes moths. In this country there are six species, at least, that attack museum materials and household fabrics, but of these only four have proved serious household pests in America. All species are capable of subsisting upon dried animal remains, and thrive upon them perhaps as well as upon the fine fabrics of wool, hair, feathers, fur, and silk.

Anthrenus scrophulariae L., A. museorum L., A. fasciatus Hbst., A. lepidus LeC, A. verbasci L., and Attagenus piceus Oliv.

Anthrenus scrophulariae L., A. verbasci L., A. fasciatus Hbst., and Attagenus piceus Oliv.

Carpet beetles pass through life cycles, or generations, consisting of egg, larva or grub, pupa, and adult or beetle. These stages differ greatly in appearance. The beetles are broadly oval and about three-sixteenths to one-fourth of an inch long; black, but with this blackness often obscured by tiny red, orange, brown, yellow, or white scales which form color designs characteristic of the species. These scales, which are modified hairs, are easily rubbed off, revealing the black color of the body beneath. The larvæ, or grubs (as the larvæ of beetles are often called) are brownish or black and variously clothed with stiff hairs, as shown in Figures 1 and 8, or with a long tuft of hairs at the end of the body, as shown in Figure 5. Carpet beetles pass through not more than two generations annually, and more often only one, and there are records of certain individuals requiring much longer, even three years, to complete their growth. The following accounts are given of the four most important species.

THE COMMON CARPET BEETLE.

Anthrenus scrophulariae L.

The common carpet beetle was known as the carpet beetle in the years following its introduction into America when floors were more commonly than, now covered entirely with carpets that were tacked down along the edges, thus giving the larvæ an undisturbed shelter favorable to their development. Originally a pest in Europe, where it is still common, it was introduced into this country about 1874, probably at Boston and New York simultaneously. No stage of this common carpet beetle is longer than three-sixteenths to one-fourth of an inch. The general proportions of larva, pupa, and adult are shown in Figure 1. The rich reddish brown larvæ are clothed with stiff dark brown hairs which are longer around the sides, and still longer at the ends, than upon the back.

The larvæ feed upon carpets and woolens (Fig. 2), furs, feathers (Fig. 3), bristles, and silks. They remain secluded in dark places, hidden beneath carpets or in the folds of garments. They eat irregular holes in fabrics, but in carpets tacked to floors they are more likely to eat slits following cracks. They never cause a webbing on the fabric.

Part 2

While most conspicuous in the Northern States, this carpet beetle is frequently found in the latitude of Washington, D. C, and southward Specimens have, recently been sent from Texas and Florida. In a Washington storehouse the contents of a trunk closed for several years were found badly damaged by the larvæ.

The following account is just as applicable to-day as when written many years ago.

Howard, L. 0., in Bulletin 4, new series, Division of Entomology, United States Department of Agriculture, pp. 58-59. 1896.

The adult insect is a small, broad-oval beetle, about three-sixteenths of an inch long, black in color, but is covered with exceedingly minute scales, which give it a marbled black-and-white appearance. It also has a red stripe down the middle of the back, widening into projections at three intervals. When disturbed it "plays 'possum," folding up its legs and antennæ and feigning death As a general thing the beetles begin to appear in the fall, and continue to issue, in heated houses, throughout the winter and following spring. Soon after issuing they pair, and the females lay their eggs in convenient spots. The eggs hatch, under favorable conditions, in a few days, and the larvæ, with plenty of food, develop quite rapidly. Their development is retarded by cold weather or lack of food, and they remain alive in the larval state, in such conditions and particularly in a dry atmosphere, for an almost indefinite period molting frequently and feeding upon their cast skins. Under normal conditions, however the skin is cast about six times, and there are, probably, in the North, not more than two annual generations. When the larva reaches full growth the yellowish pupa is formed within the last larval skin. Eventually this skin splits down the back and reveals the pupa, from which the beetle emerges later. The beetles are day fliers, and when not engaged in egg laying are attracted to the light. They fly to the windows, and may often be found upon the sills or panes. Where they can fly out through an open window they do so, and are strongly attracted to the flowers of certain plants, particularly the family Scrophulariaceæ but also to certain Composite, such as milfoil (Achillea millefolium). The flowers of Spiræa are also strongly attractive to the beetles. It is probable, however, that this migration from the house takes place, under ordinary circumstances after the eggs have been laid.

In Europe the insect is not especially noted as a household pest, probably owing to the fact that carpets are seldom tacked down. In fact, the writer believes that only where carpets are extensively used in this way are the conditions favorable for the great increase of this insect. Carpets once tacked down are seldom taken up for a year, and in the meantime the insect develops uninterruptedly. With the more general use of polished floors, and rugs which are often taken up and beaten, there is little doubt that the "buffalo bug" will eventually cease to be a household insect of importance. The insect is known in Europe as infesting museums, but has not acquired this habit to any great extent in this country. It is known to have this habit in Cambridge, Mass., and Detroit, Mich., as well as in San Francisco, Calif., but not in other localities. In each of these three cases it was imported from Europe in insect collections.

THE BLACK CARPET BEETLE.

Attagenus piceus Oliv.

The black carpet beetle derives its common name from the black, unadorned color of the adult. Its larva is reddish or golden brown, long and slender, with a characteristic tuft of long hairs at the end of its body. It curls up and "plays 'possum" when disturbed. A glance at Figure 5 will be sufficient for the identification of this unique carpet-beetle larva.

Widespread in Europe and Asia, it first attracted attention in America in 1854. Since then it has become widely distributed throughout the United States, often being the most injurious of the carpet beetles, especially in the more southern States. It is the carpet beetle most commonly referred by housewives to the department for identification. It feeds upon household fabrics of wool, feathers, fur, hair, and silk, and also upon cereals and cereal products, seeds, and dried animal remains, hence has many opportunities for existence in warehouses and barns as well as in houses.

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