By Walter Ebeling
There are about 260 species of anobiids in the United States, the majority of which feed on dead wood. However, 2 species, the cigarette beetle (Lasioderma serricorne) and the drugstore beetle (Stegobium paniceum) are important pests of stored food products. Anobiids are widely distributed, and in some parts of the world, for example in Europe and New Zealand, they are much more important than in the United States. They attack mostly sapwood, but can extend their attacks into heartwood, and they attack both hardwoods and softwoods.
Anobiids range from 1.1 to 8 mm in length, and are highly variable in body form, ranging from narrow and elongate to nearly circular from the dorsal aspect. When viewed from above, the hoodlike or "bellshaped" pronotum usually conceals the head, as in the case of the Bostrichidae and Ptinidae, but is unlike that of the true powder-post beetles (Lyctidae), in which the head is not hidden when viewed from above. The last 3 segments of the antennae are usually lengthened and broadened, or simply lengthened, but in some species the antennae are either serrate (sawtoothed) or pectinate (combshaped). (The antennal clubs of lyctus have only 2 segments.) The tibiae lack the spurs found on the tibiae of the lyctids and bostrichds. The tarsi are 5-segmented, with divaricate (widely separated) claws.
Illustrations of some of the anobiids that have been recorded as pests in the United States are shown in figure 115.
The potential for damage from the furniture beetle in the United States is indicated by the estimate made by Hickin (1963a) that at least 50% of the buildings of Great Britain contained an active infestation by this species, and possibly 20% of those built since World War II were infested. In that region, the furniture beetle is the principal species involved in "woodworm" damage - a large portion of the business of pest control operators. The beetle attacks structural timbers, paneling, flooring, and furniture In Germany, it is said to infest "nearly every building," and in New Zealand, it is believed to occur in every house that has been in existence more than 15 years. As the common name implies, the insect commonly infests furniture and other wooden articles.
In the United States, the furniture beetle is widely distributed, but has nowhere attained the importance it has in Europe. It is fairly common in the East, but not along the Pacific Coast, where infestations are usually isolated in imported furniture. The species is confined to the temperate regions of the world, and is not likely to become a pest in tropical regions except at high altitudes where the climate may be suitable for its development.
Even in temperate regions where it is well established, the incidence of infestation and the parts of a building infested can be greatly influenced by differences in climate within a small area. Thus, in Norway A. punctatum was found as frequently in attics as in cellars near the coast where summer temperatures were low, whereas relative frequency of infestation in attics decreased with increasing distance from the coast because of increasing summer temperatures, affecting attics more than cellars (Knudsen, 1967).
The furniture beetle attacks only well-seasoned lumber, provided the surface offers ovipositional sites, and it attacks wood only if the bark is removed. Exit holes of this species are never seen in the bark (Hickin, 1963a, b). Oviposition is greatly reduced on normally favored wood if it is finely sandpapered, painted, or varnished, all of which eliminate oviposition sites (Kelsey et al., 1945). According to Hickin (1949), it is rare for softwood to be attacked until about 20 years, and the sapwood of oak about 60 years, after it has been cut. However, exit holes have been found in birch plywood as little as 5 or 6 years after being cut.
Description. The furniture beetle (figure 115, A) is 4 to 6 mm long, cylindrical, reddish brown to dark brown, with longitudinal rows of pits on the elytra. These punctures are clearly visible through the fine, yellowish hairs that cover the beetle. As in all anobiids, the head is not visible from above; this distinguishes adult anobiids from the lyctids. The head has a prominent frontal protuberance, and the antennae are 11-segmented with the last 3 segments enlarged so that the 3 together are longer than the first 8 segments combined (White, 1962).
The grayish-white larva is about 6 mm long. Spinules occur on the first 7 abdominal segments, and are absent on the last 3 segments. On the first 6 segments, the bands (transverse markings) have 2 rows of spinules, and on the seventh segment the band has only a single row. A tubular projection or air tube on each spiracle is about equal to the length of the spiracle itself, and is longer than the projections on the spiracles of other common anobiid larvae. As stated earlier, anobiid larvae differ from lyctid larvae in not having a greatly enlarged posterior spiracle and in leaving 5-segmented legs, the terminal segment with a claw (figure 108). The tunnels formed by the larvae, mostly along with the grain of the wood, are loosely filled with frass. The frass consists of cigar- shaped pellets composed of minute fragments of the chewed wood. In severe infestations, large amounts of frass may be forced out of old exit holes, but "powdering" does not occur to the same extent as with lyctid beetles (Hickin, 1963a).
Life Cycle. Adults emerge in the spring from pupal cells just below the surface of the wood. They mate soon after emergence, and a day later the female lays her eggs in a crack or crevice in the wood (figure 116), in rough end-grain, rough-sawed timber, unplaned wood where the grain is open, or just inside old emergence holes (Hickin, 1963a, b). The eggs are easily seen with the unaided eye, appearing like groups of "oval pearls," but are often slightly deformed when forced into creviccs during deposition (Hickin, 1963). The average number of eggs laid has been reported to be 18 by Kelsey et al. (1945), 28 by Hickin (1963a) and, in the laboratory, 54.8 by Spiller (1964). The eggs ordinarily hatch in 6 to 10 days. Spiller (1949) observed either no hatching or impaired hatching at relative humidities below 60%.
Outdoors, the larvae require about a year for development, and will pupate for 2 to 3 weeks in a cell just below the surface of the wood. Indoors, the life cycle may require 2 to 3 years or more; this may result in a staggering of generations, so that all stages may be found in the wood at any one time. The longer indoor developmental period is presumed to be the resut of a lower moisture content of the wood (N. E. Hickin, correspondence)
The deathwatch beetle is so named because of a mating signal produced by each sex by striking its head against the surface on which it stands. A female captured immediately after emergence was placed in a small box, where she continued to live for 10 weeks. During this period, she would respond in kind when a tapping noise was made with a pencil within a few meters of the box. This tapping was once considered to be a foreboding sound or death signal by superstitious people (Gahan and Laing, 1932). Deathwatch beetles seldom if ever fly, although they will sometimes flutter their wings when thrown into the air.
Wood must be partially predigested by fungi before the deathwatch beetle can utilize it. In nature, it attacks several hardwood species. Indoors, it infests hardwood timber that was at some time infected with fungi. In England, where so many buildings are constructed of oak, this is the principal timber infested. The timbers most likely to be attacked are those soaked by rain or that are in poorly ventilated locations. Infestation always originates in hardwood, but can extend into adjacent softwood. Heavy furniture is often infested, particularly if made of oak or chestnut. Deathwatch beetles can also attack books (Fisher, 1937; Hickin, 1963a). In the United States, X. rufovillosum is much less important as a pest than it is in Europe. It is common in certain parts of eastern North America, but not along the Pacific Coast (Linsley, 1943b).
Description. The deathwatch beetle adult (figure 115, B) is about 7 mm long, dark grayish brown, with a pattern of yellowish, scalelike hairs on the pronotum and elytra; if the elytra are old and worn, the beetle may appear more reddish and shining (Hickin, 1963b). Xestobium rufovillosum does not have longitudinal rows of small pits on the elytra, such as are present in the furniture beetle, Anobium punctatum. The antennae are 11-segmented, but much shorter than those of A. punctatum, and the last 3 segments are somewhat enlarged and as long as the preceding 5 combined (White, 1962). Circular emergence holes of the deathwatch beetle are about 3 mm in diameter - about twice as large as those of the furniture beetle. The frass consists of relatively large lenticular or "bunshaped" pellets, characteristic of the species (Parkin, 1933).
The creamy-white larva of the deathwatch beetle is the largest of the anobiid larvae, being up to 11 mm long. The head is yellowish, and the mandibles are nearly black. The eyes consist of 2 black spots on each side of the head, compared with 1 black spot in A. punctatum larvae. Spinules occur dorsally on the first 8 abdominal segments, and laterally and ventrally on the ninth and tenth segments. Unlike the spiracles of A. punctatum, those of X. rufovillosum have a very short, tubular projection or air tube (Parkin, 1933).
Life Cycle. In England, where the deathwatch beetle has been investigated extensively, the adults begin to appear in April and May, and their tapping noise is then commonly heard. Unlike the furniture beetle, the adults may remain in their pupal cells until the following spring. They mate soon after emergence, and then die in a few weeks.
The female lays her eggs in small clusters, usually of 3 or 4, on rough surfaces, in cracks, or just inside the emergence holes. When first laid, the eggs are sticky and adhere together. They are whitish, oval, smooth throughout, and about twice as large as those of the furniture beetle. Usually, 40 to 60 eggs are laid, but up to 201 have been recorded. They hatch in 2 or 3 weeks. Under favorable conditions of food and temperature, the deathwatch beetle may go through its life cycle in a year, but this period may be prolonged to as much as 10 years. Outdoors, in oak infected with fungi, the life cycle has varied in duration from 3 to 7 years, and indoors it is believed to average about 4.5 years (Hickin, 1963a).
Other Anobiids
The eastern deathwatch beetle, Hemicoelus carinatus (Say) (=Hadrobregmus) (figure 115, C), is reddish brown to blackish brown, and is 3.4 to 6.8 mm long. The antennae are 10-segmented, with the last 3 segments (club) as long as or longer than the pronotum in the male, but shorter than the pronotum in the female. It is widely distributed in eastern North America, and has been recorded from ash, basswood, maple, beech, and elm, and in sills, joists, beams, and flooring. The larvae often cause much damage (Payne, 1936; Linsley, 1943b; Craighead, 1950; Wright, 1959). Payne called attention to the fact that the damage caused by H. carinatus resembled that caused by lyctid beetles in hardwoods, except that the emergence holes were a little larger and the frass was somewhat coarser.
The Cailifornia deathwatch beetle, Hemicoelus gibbicollis (LeConte) (=Hadrobregmus) (figure 117), is similar in appearance to the eastern species, but has 11-segmented antennae, and the pronotum is distinctly narrower than the base of the wing covers, whereas in Hemicoellis carinatus they are about the same width. Linsley (1943b) stated that the California deathwatch beetle bred in old, well-seasoned Douglas-fir studs, joists, and supporting timbers along the Pacific Coast, and was especially common in basement timbers of buildings 20 years old or more figure 118). Hatch (1946) found serious damage from this species to the weathered boards of spruce in the flooring of a porch. In the areas where it occurred, Linsley considered H. gibbicollis to be the most serious pest among the powderpost beetles in the broad sense of the term.
Ernobius mollis (L.) appears somewhat like a large Anobium punctatum. The short, golden hairs of the newly emerged adult produce a light shade of golden brown, but when some of the hairs are lost, the beetle becomes more uniformly brown. The elytra are less horny, and lack the longitudinal rows of pits characteristic of A. punctatum. Ernobius mollis oviposits only in softwoods, and then only when the bark is attached. Hickin (1963a) found that when the bark was stripped off, the infestation rapidly died out. In the United States, however, E. mollis occasionally does much damage to pine and spruce flooring (Craighead, 1950).
White (1962) listed 7 species of Ernobius occurring in the eastern United States, including E. granulatus LeConte. This species has unusually large eyes. It is 2.3 to 4.3 mm long, reddish brown, with elytra yellowish apically, appendages and abdomen yellowish brown, and with a very fine, short, yellow pubescence. The last 3 antennal segments are very long. Ernobius granulatus has been recorded from many eastern states.
Despite the usual propensity of anobiids to attack old, seasoned wood, some species can destroy weakened shoots of young pine trees, and are scavengers in the cones of conifers. In California, the species most commonly involved is Ernobius punctulatus (LeConte). The beetles are most abundant where dead pine branches have been allowed to accumulate (Doane et al., 1936).
Priobium sericeum (Say) (= Trypopitys) (figure 115, D) is 4.9 to 6.2 mm long, with the head deeply retracted within the prothorax. It is reddish brown to brown, covered with a short, yellowish pubescence. Antennal segments 3 to 7 are distinctly serrate, 8 to 10 are somewhat serrate, and segment 11 is rather narrow and elongate. The combined length of the last 3 segments of the antennae equals the combined length of the 5 or 6 preceding ones (White, 1962). This species is occasionally found in flooring, sills, and in buildings in the eastern states.
In southern California, Priobium punctatum (LeConte) (= Trypopitys), a species closely resembling the furniture beetle, Anobium punctatum, has been found on oak door casings and flooring and in maple wainscoting. This species has also been found in Monterey cypress and pine (Doane et al., 1936).
Ptilinus ruficornis Say (figure 115, E) is 2.8 to 4.8 mm long. The male is completely black, or black with light-brown elytra. The female is bright reddish brown to dark reddish black, with the pronotum bright reddish brown. Both sexes have reddish-brown to reddish-yellow appendages. The antennae of the female are distinctly serrate, whereas those of the male are actually branched, with each branch, on segments 5 to 10, nearly or quite as long as the combined length of segments 1 to 10. The pronotum of both sexes is roughened anteriorly, but particularly so in the female. This species infests beech, maple, oak, sycamore, mesquite, and other hardwoods, and is a rather common and injurious pest of woodwork and of stored wood products (Craighead, 1950). In California, another species, Ptilinus basalis LeConte, along with the bostrichid Scobicia declivis, attacks California laurel (Umbellularia californica) so readily that laurel has had to be nearly abandoned for interior finishing, for which this very beautiful wood is well suited (Doane et al., 1936).
Xyletinus peltatus (Harris)(figure 115, F) is 3.4 to 6.3 mm long, reddish brown to brown, with a fine, short, yellowish pubescence. Its eyes are large, those of the male separated by about 2 times, and those of the female about 3.3 times, the width of the eye as seen from the front. The 11-segmented antennae are moderately serrate, and the last 3 segments are slightly enlarged. The elytra are finely, not deeply, striate (furrowed), with the interval between striae feebly convex (White, 1962).
Xyletinus peltatus is widely distributed throughout the eastern states, and is the most frequently collected species of the genus (Wright, 1959; White, 1962). Williams (1973) considered it to be the most common anobiid in the southeastern states. It often does great damage to cellar joists and flooring in damp buildings, particularly when they are unoccupied or closed up. This species appears to require moist conditions and associated fungi. When conditions are optimum, it can attack both softwoods and hardwoods so severely that complete structural failure will occur. However, it has been known to manifest distinct preferences for certain wood species. Williams (1973) gave an example of such a preference in lumber stored in an old earthen-floor barn infested with X. peltatus. The wood species were yellow poplar, cypress, and western pine. The cypress and western pine were not infested, but radiographed sample boards of yellow poplar contained an average of 72 larvae per sq ft (929 sq cm), and yellow-poplar molding contained about twice that number.
Prevention and Control of Powderpost Beetles
The following discussion pertains to infestation by the true powderpost beetles (Lyctidae), false powderpost beetles (Bostrichidae), and deathwatch beetles (Anobiidae). Prevention of losses from these beetles should begin at the lumbermill, and be continued in lumberyards, builders' lots, and other areas in which lumber may be stored before use.
An extremely important phase of prevention is sanitation. In nature, beetles breed in old and dried wood, such as dead branches and limbs of trees, and material of this kind should be burned if it exists near piles of lumber. The same may be said of old lumber and other materials that are subject to infestation. Storage areas should be inspected periodically. Infested lumber should be burned, and pallets, stacking sticks, stakes, platforms, and shelves should be protected against attack. Paraffin wax, varnish, shellac, and paint will fill the pores in which lyctid beetles lay their eggs, and thereby prevent infestation. Infestation by lyctid beetles can be avoided merely by using only softwoods for the pallets, stacking sticks, etc. However, oak is preferred, despite its susceptibility to attack, because it is stronger, more durable, and does not shatter or splinter so easily as coniferous woods.
Firewood stacked outdoors is frequently a source of beetles that can infest structural wood after the firewood has been carried into the house. Other woodborers that may not be able to infest seasoned wood, but are nevertheless nuisances and sources of anxiety when found crawling or flying about in the home, can also emerge from firewood.
Green lumber can be protected against powder-post beetles by submerging it in an insecticidal cold-water emulsion. Similar protection for seasoned wood can be obtained with a solution of insecticide and deodorized kerosene. Insecticides that have proved to be effective in this connection are 5% toxaphene, 2% chlordane, 0.5% dieldrin, and 0.5% lindane. Immersion for 3 minutes gives protection for at least 3 years. A 5-minute dip in 5% pentachlorophenol in a light fuel-oil base is also said to be effective, and this same compound, added to the insecticide emulsions or solutions just mentioned, acts as a fungicide. Protection for 1 season can be obtained with only a 10-second immersion in these insecticides or a 15-second dip in a 5% borax solution heated to 180 �F (82 �C). Following any of these treatments, the treated lumber or wood products can be painted or varished after a reasonable drying period (NPCA, 1961).
Some homeowners would certainly not want to have insecticide-treated lumber used for such articles as kitchen cabinets and baby cribs. A concentration of 0.3% dieldrin or aldrin added as an emulsifiable concentrate to glue prepared for plywood manufacture has been found to provide good protection of plywood against Anobium punctatum in New Zealand (Harrow et al., 1970).
All stages of lyctid beetles can be killed by heat in kilns. In table 3, the periods of exposure of wood of various thicknesses that are required to check damage by powderpost beetles at different temperatures and relative humidities are given. The required periods of exposure increase with increasing thickness of the wood, decreasing temperature, and decreasing relative humidity (St.George, 1970).
The type of treatment selected for control of powderpost beetles will depend on a number of circumstances, among them the size of the infested area. If the infestation is localized, the application of a toxic solution to the infested wood surface or a liquid gas volatilized under a tarpaulin may be considered. Infested furniture can be fumigated in a gastight fumatorium. For the treatment of a large infested area, such as an entire house, tent fumigation, such as practiced for dry-wood termite control, may be the only practical procedure. Even if one finds only a few beetles, believed to be a localized infestation, a complete fumigation of the entire structure is the most reliable way to control the infestation. It is often difficult to locate incipient infestations. However, even with complete fumigation of a building, incomplete control of lyctid beetles occurs in about 10% of the treatments.
Toxic Solutions
For treatment of raw hardwood flooring, unfinished paneling, or structural timbers already infested with powderpost beetles, 2% chlordane or 5% lindane, dissolved in a moderately volatile light oil such as deodorzed kerosene, have been successful when sprayed or painted on the wood at 1 gal per 100 sq ft (4 L per 9 sq m) of surface or until the wood can no longer absorb the liquid. (Solutions of 5% DDT and 0.5% dieldrin are no longer registered for this purpose.) On finished wood, the entire sur face should be treated evenly with a coarse, fan-type spray, but not to the point of runoff puddling. Repeated applicationsmay be necessary to obtain absorption of the reccommended quantity. Each successive application should be made after the preceding one has been absorbed, but before the surface is completely dry. Unless the treatment is applied to thew ground floor, care should be exercised to avoid staining the ceiling and walls below the treated floor. Treated floors should not be walked on, and no objects should be placed on any treated surface for at least 24 hours. Since the treatment can destroy wood finishes, it is advisable to treat a small, ionconspicuous area for preliminary observation before treating infested finished wood. Damaged surfaces must be resanded, refinished, and rewaxed. Sanding, of course, can also be done before treatment, particularly if the floor happens to need it. A few beetles may occasionally emerge after treatment, but the toxic residue will prevent reinfestation. When parquet or block flooring is bound to concrete slab by adhesive, the oil carriers for insecticides can deteriorate the adhesives. In such cases, the entire building should be fumigated.
Smith (1968) was able to prevent infestation of ash lumber by Lyctus powderpost beetles during air-drying, which commonly requires 3 to 18 months. Ash is highly susceptible to infestation. Boards were dipped in lindane emulsions of various concentrations for 10-second periods and then stood on end in a rack to dry for 1 hour. Twenty boards, 1.2 m long and 10 to 20 cm wide, were used for each lindane concentration. The boards were then placed in stacks, with 1.5-cm pine spacers between them to keep them apart. About 12 months after treatment, the boards were exposed to infestation by introducing infested boards from laboratory-reared colonies. All surfaces were examined annually. With 0.06% lindane emulsion, the number of Lyctus beetle holes varied from none the first year to 6.5 the third year, compared with 22 and 295, respectively, in the untreated controls. At 0.25% concentration of lindane, no holes were found during the 3-year period. Since the normal storage period was not longer than 18 months, Smith concluded that a 10-second dip in 0.06% lindane emulsion was adequate for protecting lumber from Lyctus beetles during air-drying. A 25% increase in lindane concentration sufficed for protection against ambrosia beetles, which are discussed later.
For the treatment of timbers such as those used in log cabins, rustic bridges, rustic furniture, and the like, a 0.5% lindane solution in petroleum oil, sprayed onto the surface of the bark or wood, is effective for the control of bark beetles or borers that have only recently attacked and have not penetrated deeper than the outer surface of the wood. Wood that has been attacked for a longer period should be soaked for at least 5 minutes.
Toxic Solutions for Anobiid Beetles
Anobiid infestations usually begin in crawl spaces, particularly if the soil is wet, for the wood then contains more moisture, favoring infestation. Fortunately, the infestation spreads slowly. Control is least difficult and least expensive when the beetles are still confined to the substructure and before they have spread upward into the walls (Williams, 1973). Extensive research was done by Spink et al. (1966) at Louisiana State University on the control of the anobiid Xyletinus peltatus. The external signs of infestation by this beetle were entrance holes less than 1.6 mm in diameter and exit holes about 3 mm in diameter. The number of holes might exceed 200 per sq ft (929 sq cm). Dieldrin at 1% and chlordane at 2% concentrations, in either water or kerosene, gave complete control when applied with a 1-gal (4-L) compression sprayer to the inner sides of 2 joists and the subflooring between them. The liquids were sprayed back and forth over the infested wood until no more liquid was absorbed. There were 4 replications of each treatment. Pretreatment and post-treatment evaluations were based on the number of pellets falling from the infested areas. The tests were stopped after a year.
Another test was made in 6 houses. Dieldrin at 0.15% and 1% and chlordane at 1% and 20% concentrations in water or kerosene were applied to subfloor wood members infested with Xyletinus peltatus. The liquids were applied with a motorized 15-gal (57-L) sprayer, with pressure held to a minimum. The spray was applied in a solid, cone-type pattern, using a No. 5 nozzle disk with a 2-mm aperture. The sprays were applied back and forth over the wood until the timbers were saturated. Approximately 4 gal (15 L) of kerosene solution or 4.5 gal (17 L) of water solution were required for treating 100 sq ft (9 sq m) of infested wood surface. No spreaders or stickers were added to the spray liquids because the tests were made to determine whether sprays as used for termite control and applied with similar equipment, but with reduced pressure, could control anobiid beetles. Evaluations of efficacy were made as in earlier tests, and no further evidence of infestation was seen after any of the treatments.
When the beetle larvae bore into wood, they fill their entrance holes with frass. Tests with water-soluble dye have shown that the frass acts as a wick to carry the insecticide deeply into the wood.
Fumigation for Powderpost Beetles
Methyl bromide fumigation for drywood termites was discussed under the heading "Fumigation." Fumigation for powderpost beetles can be done in the same way, but instead of a concentration of 2 lb per 1,000 cu ft (0.91 kg per 28 cu m) of building space, 3 lb (1.36 kg) is generally recommended for a 24-hour period, provided the temperature is over 60 �F (16 �C), the space being fumigated is properly sealed, and a minimum of 0.5 lb per 1,000 cu ft (0.23 kg per 28 cu m) of gas remains at the end of the 24-hour period of fumigation. Under some circumstances, a higher initial dosage or additional gas sometime during the fumigation period may be required. Methyl bromide fumigation should be done only by a licensed and experienced operator.
Movable items such as furniture can be fumigated in vaults or fumatoriums designed for this purpose. Some pest control firms have such facilities (figure 119). Because of tighter sealing and controllable temperature, either the dosage or exposure can be decreased below that which is required for effective building fumigation. For vault fumigation with methyl bromide, the usual relationships of dosage and period of exposure are, per 1,000 cu ft (28 cu m): 1 lb (0.45 kg) for 24 hours, 3 lb (1.36 kg) for 8 hours, or 9 lb (4.08 kg) for 3 hours. When it is possible to provide partial vacuum, dosage or time can be even further decreased (NPCA, 1961).
Beetle-infested timbers may also be placed in a pile, covered with a tarpaulin, and fumigated with methyl bromide at the rate of 4 lb per 1,000 cu ft (1.82 kg per 28 cu m) of air space. The gas should be confined for about 72 hours. Methyl bromide is an odorless gas and deadly poisonous if inhaled (St. George, 1970).
Sulfuryl fluoride (Vikane), often used for fumigation of drywood termites, is not recommended for control of lyctid beetles because of its relatively low efficacy against the eggs. About 10 times the dosage used in drywood termite fumigation is required to kill lyctid eggs.
An aluminized, neoprene, portable, gastight fumigation tent, with walls and floor continuous, and supported by a collapsible tubular metal pipe frame (figure 120) was developed in England for on-the-spot fumigation of small commodities. It is 7 ft wide, 7 ft high, and 9 ft deep (about 2 m and 2.75 m) and has a 300-cu ft (8.4-cu m) capacity. It has 2 types of gastight seals for the front opening: an industrial metal zipper or a pressuretight channel that completely seals all edges of the flexible flap opening. A 10-in. (25-cm) fan is operated in the tent for a period of 3 minutes, immediately after the fumigant is introduced, to thoroughly distribute the gas (Burns Brown and Heseltine, 1964). A metering device is supplied with the tent that delivers the entire contents of a 1-lb (0.45-kg) can of methyl bromide, supplying a concentration that is the equivalent of a little over 3 lb per 1,000 cu ft (1.36 kg per 28 cu m). As stated above, in vault fumigation the period of exposure for this concentration of methyl bromide is normally 8 hours.
If a lower rate of dosage is required for the commodity fumigated, a shorter exposure period should be utilized, rather than using less gas.
Fumigation is very expensive, and when an infestation of powderpost beetles is known to be confined to a section of hardwood flooring, a localized treatment may be appropriate. S.T.D., proprietary 15.17% solution of the liquid fumigant ethylene dibromide and 4.03% chlordane, in deodorized kerosene, may be mopped evenly over the infested area, using just enough to wet it without leaving puddles. On upper floors, care must be taken to avoid using so much liquid that some of it will stain the ceiling below. The treated area is covered with a polyethylene tarpaulin, the edges of which are taped down to the dry floor surrounding the wet area, and the tarp is left in place for 24 hours. It is then removed, and the windows are opened to allow for complete ventilation.
Occupants are kept out of the room(s) being fumigated during this 24-hour period and the additional period required to completely remove the gas (Ehmann, 1961; NPCA, 1961). Repeated treatments may be required, but pest control operators in the Los Angeles area advise us that the surprisingly few "callbacks" after localized treatment for powderpost beetles indicate to them that their treatments are generally successful. Such pest control operators usually offer a 1-year guarantee on their work.
In another form of localized treatment for powderpost beetles, some pest control operators place a tarpaulin over infested areas, such as hard wood wall cabinets, and release methyl bromide under the tarp.
The localized treatment with ethylene dibromide, when properly performed, usually will not harm a varnished floor surface but will dissolve the wax coating.
In cases where parquet or block flooring is laid directly on a slab to which it is bound by adhesive, the liquid fumigant should be applied in a pan under the tarp so that the ethylene dibromide will contact the floor only as a gas and not as a liquid; otherwise, the adhesive under the floor may be dissolved. Plywood is more difficult to penetrate with a gas because of the glue layers, and increased dosages and extremely careful application techniques are required to ensure good results.
The homeowner may decide to consider removal and destruction of infested wood as an alternative to fumigation (NPCA, 1961).
   
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