IPM for Fabric and Pantry Pests

Home , Drugstore beetle, Pantry, Ptinidae

Chapter 9 IPM for Fabric and Pantry Pests

Introduction varied in appearance (see Table 9-1). Damage Their bodies are covered with small Dermestid beetles, such as carpet and scales or hairs, which are visible with a Dermestid beetle holes are usually hide beetles, are sometimes referred magnifying glass. Larvae are brown- concentrated in a few areas and can to as fabric pests. They can digest ker- ish, 1/8 to 1/2 inch long, and charac- be quite large. Carpet beetles dam- atin, the “hard” protein of which hair, teristically hairy or bristly. age materials made from wool such horns, nails, claws, hooves, feathers, as sweaters, uniforms, felt, wool yarn, and reptile scales are formed. These The larval stage is the most damag- etc. They can also destroy insect col- insects can also attack a wide variety ing. Females lay eggs throughout the lections, furniture, and carpets. Hide of other natural materials and even year, and the eggs hatch after less beetles feed on animal carcasses and some synthetic ones. than two weeks. The larvae feed for hides, and also damage furnishings, varying periods, depending upon the carpets, and fabrics. Some species also Identification and Biology species and the environmental condi- infest stored, dried foods such as ce- tions. When ready to pupate, the lar- real (Table 9-2 provides more detailed Adult beetles are small and have short, vae may burrow farther into the food information on the food preferences clubbed antennae but are otherwise or wander and burrow elsewhere. of both hide and carpet beetles).

Table 9-1. Important Carpet or Hide Beetles (Dermestids)

Common Name(s) Scientific Name Description of Adults Furniture carpet beetle Antbrenus flavipes • 1/10 inch to 1/5 inch long • definite cleft at rear • mottled with black, white, and yellow scales Varied carpet beetle A. verbasci • 1/10 inch to 1/8 inch long • mottled with white, brownish and yellowish scales Black carpet beetle Attagenus megatom • 1/10 inch to 1/5 inch long, oval • Shiny black and dark brown with brownish legs Black larder beetle Dermestes ater • 3/10 inch to 2/5 inch long • black with yellowish gray hairs • black rounded and hook-shaped spots on underside of abdomen Larder beetle D. Lardariu • 3/10 inch to 2/5 inch long • dark brown with pale grayish yellow hair • yellow band at base of wing covers with about six black spots Hide beetle D. Maculatus • 1/5 inch to 2/5 inch long • black with white hairs on sides and undersides • apex of each wing cover comes to a fine point Warehouse beetle Trogoderma variabile • 1/8 inch long • brownish black

Beetle Food Sources Furniture carpet beetle horse-hair filled furniture, wool, hair, fur, feathers, bristles, horn, tortoise shell, silk, animal (Anthrenus flavipes) excreta, stained linen, cotton, rayon, jute, Softwood, leather, bags, dried silkworm pupae and cocoons, dead mice, dead insects, dried cheese, old grain, casein, dried blood, and the glue of book bindings Varied carpet beetle nests of bees, wasps, and spiders; carpets, woolen goods, skins, furs, stuffed animals, leather (A. verbasci) book bindings, feathers, horns, whalebone, hair, silk, fish manure, dried silkworm pupae, rye meal, cacao, corn, red pepper, and dead insects in collections Black carpet beetle feathers, dead birds, birds’ nests, bird manure, dry horse and cow carcasses, seeds, grains, (Attagenus megatoma) cereals, woolen rugs, clothing, carpeting, felts, furs, skins, yarn, velvet, silk, hair-filled mattresses, upholstered furniture, wool-filled blankets, house insulation with sheep wool or cattle hair, meat, insect meal, kid leather, milk powders, casein, books, cayenne pepper, dried pupae of silkworms, pet food, spilled flours, and pollen (for adults, particularly of Spiraea) Black larder beetle mouse cadavers in walls of building; partially burned food and other kitchen wastes in (Dermestes ater) incinerators; pet foods Larder beetle stored ham, bacon, meats, cheese, dried museum specimens, stored tobacco, dried fish, dog (D. lardarius) biscuits; can tunnel slightly in wood; can penetrate lead and tin but not zinc or aluminum; pest of silkworm cultures; reported to attack newly hatched chickens and ducklings Hide beetle prefers hides and skins; used to clean carcasses; known to survive on smoked meat and (D. maculatus) dried cheese, but cannot live on fat alone; larvae can tunnel short distances into wood Warehouse beetle prefers barley, wheat, animal feeds, grains, and pollen; also found in seeds, dead animals, (Trogoderma variabile) cereals, candy, cocoa, cookies, corn, corn meal, dog food (dried and “burgers”), fish meal, flour, dead insects, milk powder, nut meats, dried peas, potato chips, noodles, spaghetti, and dried spices

Detection card under the open end. Seal the jar is rarely moved, in wall and floor and Monitoring and place it in the freezer overnight. cracks, in cracks behind filing The dead insect can be examined cabinets, shelves, or other built- Look for holes in fabric, for larvae, with a magnifying glass or taken to a in items that may not be flush cast skins of beetle larvae, or insect professional for identification. with the wall, behind baseboards, excreta in stored materials. moldings and window trim, and in An inspection should include the fol- cold air and heater ducts Carpet beetle larvae may be found lowing locations: wandering far from their food, par- • around stored animal specimens, • around carpets or furniture feathers, garments, blankets, or ticularly to pupate so they are some- covered or filled with susceptible times encountered on materials they other items made of susceptible materials; infestations may be un- materials do not actually eat. Also, adult carpet der the slipcovers, where it is dark beetles do not shun light and may be and quiet, or in the pads under the • around bags or boxes of dried found crawling on windows. This is carpet milk, fish or meat meal, dog food, often the first place they are noticed. etc; note that carpet beetles can • around accumulations of lint and bore through cardboard and paper These beetles are easy to catch: cover other organic debris, particularly packaging the insect with a jar and slowly slide a under and behind furniture that

88 • IPM for Fabric and Pantry Pests © The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. If the infestation does not appear to help reduce the possibility of an nests of birds, rodents, bats, bees, and large enough to account for the infestation developing. wasps, as well as from the carcasses number of pests found, or if clean- of dead animals. Remove nests in ing up the infestation does not seem Cedar Products the eaves, in the walls, or close to the to diminish their number, then a Cedar chests have long been thought walls of the building. Problems with further search should focus on less to protect against fabric pests, but it birds’ nests usually occur after the obvious sources: has been known for many years that nestlings have left. • bird, wasp, bee, squirrel, or other although cedar oil can kill very young Nests should be removed before the animal nests on, or very close to, larvae, the oil does not affect eggs, cold weather sets in and the beetles the walls of the building pupae, adults, or larger larvae, and begin searching for sheltered hiber- that cedar lumber loses its oil in only • animal carcasses or trophies, nation spots. If there is a problem a few years. Commercial repellents with rats and mice, these should insect collections, or leather or made from cedar, cedar oil, or herbs horn goods be trapped rather than poisoned. If cannot be counted on to give ade- poisoned rodents die in inaccessible • cut flowers, or blooming bushes quate control to protect goods, either. places, their carcasses can become near open, unscreened windows food sources for fabric pests and flies. or doorways Vacuuming (See Chapter 13 for management of • incompletely incinerated garbage Accumulations of lint, human and mice and rats.) animal hair, and other organic In some circumstances, sticky traps debris in cracks and crevices of placed in areas where activity is Pantry Pests floors, baseboards, closets, and suspected may be useful for monitor- shelves provide food for fabric ing. Hang them where you suspect Stored foods can become infested pests. These areas should be cleaned you might have a problem and check with various pantry pests. They com- thoroughly and regularly to prevent them daily monly infest flour, cereals, cracked infestations. It is particularly impor- grains, baking mixes and processed tant to clean under furniture that is foods, crackers, macaroni, cured Management Options rarely moved (e.g., desks, bookcases, meats, powdered milk, dried fruits, cabinets, etc.); in closets where nuts, popcorn and spices. Insects There is rarely a need to use an fabric items, furs, and feather-filled that feed on these products may also insecticide to control carpet beetles materials are stored; and inside and infest other grain-based items such as and other dermestids. The following behind heaters, vents, and ducts. pet foods, birdseed and ornamental physical controls should be adequate. corn. Dried flower arrangements may Caulking Physical Controls also be attacked. Caulking or otherwise repairing Identification and Biology Storage in Tight Containers cracks and crevices where lint and hair can accumulate will reduce the If clean materials are placed into Indian Meal Moth number of fabric pests that are able to tightly sealed containers, they will be (Plodia interpunctella) live in the environment. Areas of par- safe from infestation. The problem ticular concern are the spaces inside The Indian meal moth (adult Figure with closets and similar storage areas cabinets where shelves do not meet 9-1) is the most common food- is that they are almost impossible to the wall and similar spaces in drawers seal because newly hatched larvae are holding susceptible materials. These so tiny they can crawl through very same habitats are likely to be inviting small gaps. to cockroaches. All grains, cereals and other similar susceptible substances should be Removal of Animal Nests stored in tight-fitting containers to Carpet beetles can sometimes move deny beetles access. Containers can into buildings from the abandoned Photo: UNL Department of Entomology be placed in the freezer for a few days Figure 9-1. Indian Meal Moth Adult

© The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. IPM for Fabric and Pantry Pests • 89 infesting moth found in schools, Dermestid Beetles homes, grocery stores and any place (Family: Dermestidae) where dried pet foods are produced As mentioned earlier, dermestid or stored. It feeds on a large variety of beetles scavenge and feed on animal stored food products, but infestations matter like dried meats, dead insects, often are started through dried pet hides and woolens. Some species, food or birdseed. Nuts are a favorite such as the warehouse beetle, varied Photo: UNL Extension in Lancaster Co. breeding source; infestations have carpet beetle and larder beetle (Fig- Figure 9-5. Cast (Shed) Skins from been found in nut caches of squirrels ure 9-3 and 9-4), have expanded their Dermestid Beetle Larva in attics and chimneys. diet and also feed on grain and grain- “skins’ will be found (Figure 9-5). based products. They are especially The larva (Figure 9-2) prefers coarse Dead adults are often found in win- common in flour and cereals but also grades of flour, whole grains, cereal, dowsills because they fly to the light, are found in candy, cocoa, cookies, dried fruits, seeds and spices. Foods trying to get outside. corn meal, nuts, pasta, dried spices, infested with these insects will have and many other dry foods. Since some of these species feed on silk webbing present, especially near woolens, infestations in the pantry the food surface. may spread and damage valuable clothing, woolens and furs. Proper cleaning and storage of natural fabrics will help prevent damage.

Sawtoothed Grain Beetle (Oryzaephilus surinamensis) Photo: UNL Department of Entomology Figure 9-3. Warehouse Beetle Adult The Sawtoothed grain beetle (Figure and Larvae 9-6) is another very common pantry pest. It does not feed on intact whole The adult beetles are small, oval and grains but feeds on many processed variously colored. The full grown food products such as breakfast food, larvae are similar in size to the adults bran, dried fruits, nuts, sugar, choco- Photo: UNL Department of Entomology for each species and tend to be cigar- late, and macaroni. It is especially Figure 9-2. Indian Meal Moth Larvae and Adult shaped and banded with dark, long fond of oatmeal and birdseed. These hairs. In some species, the larvae flat beetles can even get into sealed have a tuft of hair at the tail-end of boxes and packages of food. Adult moths are nearly 1/2-inch long the body. and have distinctive wing markings. Adults are nearly 1/4-inch long, The base of the forewing is pale grey Typically, only larvae will be seen in slender, brownish-red and active. and the outer two-thirds is reddish- infested food because the adults feed Their name comes from the six brown with a coppery luster. They on pollen and leave the food once saw-like teeth on either side of the have a distinctive way of “resting” on they have emerged from their pupal thorax behind the head. After finding the wall at an angle with their wings stage. Sometimes only the larval a potential food source, the female folded. The larvae are generally dirty- white in color with shades of yellow, pink, brown or green. Mature larvae, which are about 1/2-inch long, usually move away from the feeding site before pupating within silken cocoons. Photo: UNL Department of Entomology Photo: UNL Department of Entomology Figure 9-6. Adult Sawtoothed Figure 9-4. Larder Beetle - Adult Grain Beetle

90 • IPM for Fabric and Pantry Pests © The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. lays white, shiny eggs that hatch into store beetle. However, if the beetles yellowish-white larvae. There can be are found in food or grain products, as many as seven generations each it is most likely a cigarette or drug- year, but sawtoothed grain beetles of- store beetle. ten stop breeding in the winter unless buildings are heated and moisture is Drugstore beetles (Stegobium pani- sufficient. Adults are very long lived ceum): The drugstore beetle will feed and remain active in the winter. on bread, but it will also feed on any Photo: UNL Department of Entomology dried, food-based material. It will Figure 9-8. Adult Confused Flour Beetles Cigarette and Drugstore Beetles damage book bindings. It has been found to perforate tinfoil and sheet The biology of these two beetles is These small, stout beetles (Figure 9-7) lead and easily chews through most very similar. The primary difference locations are common in where they food packaging material. is the red flour beetle flies and the can attack pet food, cereals, spices, confused flour beetle does not. If you Cigarette beetles (Lasioderma ser- and other packaged foods. Since they see a red flour beetle crawling on ricorne): The cigarette beetle derives closely resemble each other, they are the counter, the breeding source is its name from its serious infestations often confused. The heads of both probably nearby, but not necessarily. of stored tobacco. Adult beetles are beetles are tucked under the prothorax A confused flour beetle crawling on about 1/8-inch long, light brown, and and are not visible from above. Both the counter is almost certainly from a oval. The most common food materi- are brown and about the same size. nearby food source. als include pet food, cereal, peppers, The two beetles can be distinguished spices, raisins, and seeds. by their wing covers. The wing covers Granary and Rice Weevils (Sitophilus spp) of the drugstore beetle have rows Flour Beetles (Tribolium spp) of longitudinal grooves while those These insects (Figure 9-9 and 9-10) of the cigarette beetle are smooth. There are a number of species of tiny damage whole grains or seeds. They Another distinguishing feature is the beetles that infest flour, but the two generally do not feed on flour or most common flour beetles are the cereals unless it has become caked. confused (Figure 9-8) and red flour beetles. These beetles are scavengers in Adult weevils are very similar. Both that they cannot attack whole grains are dark reddish-brown and range in but rely on other insects to damage the size from 1/8 to 3/16-inch long. They kernels first. In buildings they can be have a long snout projecting from the found feeding on flour, cracked grains, head and wing covers with distinct cake mixes, beans, peas, dried fruits, ridges.

Photo: UNL Extension in Lancaster Co. nuts, chocolate, and spices. Figure 9-7. Drugstore Beetle Adult (Left) Cigarette Beetle Adult (Right) These red and confused flour beetles are very similar: both are reddish- antenna. The drugstore beetle has a brown and about the same size, 3/16- three-segmented club while the ciga- inch long. They can be distinguished rette beetle has an antenna that looks by their antenna. The antenna of a little like a saw blade. the red flour beetle ends abruptly Figure 9-9. Granary Weevil - Adults Both the cigarette and drugstore in a three-segmented club while the beetles belong to the family Ano- antenna of the confused flour beetle biidae and can be confused with gradually enlarges toward the tip, some wood-boring beetles of the ending in a four-segmented club. In same family. It is important to have addition, the sides of the red flour the beetle identified because wood- beetle’s thorax are curved while the boring beetles have greater damage confused flour beetles thorax has Photos: UNL Department of Entomology potential than the cigarette and drug- straighter sides. Figure 9-10. Rice Weevil - Adults

© The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. IPM for Fabric and Pantry Pests • 91 Females lay eggs on seeds, kernels or from stored seeds. They are attracted 1/4-inch long, cream to tan in color other suitable foods. The larvae chew to light and are attempting to escape. and curved. Larvae usually curl their into the seed and feed on the inside Usually, there is little concern for their bodies when disturbed. Most spider of whole kernels/seeds. Pupation presence until a sack of dried beans or beetles have two or three generations normally occurs within hollowed- peas, especially homegrown, is emp- each year. out kernels or seeds. There can be tied and found full of holes. Occasion- as many as three to five generations ally, one may take a package of dried Spider beetles are mainly scavengers each year. Weevil-damaged grains beans or peas out of storage to find it but will infest grain-based products are typically hollow and have small infested with small, stout beetles with that are old, moist, and possibly round emergence holes. a short, broad snout. moldy. There is often an association with spider beetles and infestations Since they feed on whole grains, these The adult bean weevil is a short of rodents, birds, bats, or bee/wasp insects are more likely to be a prob- chunky beetle, about 1/8 inch in nests in walls or attics. These beetles lem in grain bins and warehouses, length. It is olive-brown with darker will feed and breed in accumulations but it is possible to have infestations brown and gray patches on the wing of animal excrement. Older buildings in other facilities. Most common covers. The elytra are shorter than and warehouses tend to have more sources are popcorn, birdseed, deco- the abdomen leaving a few segments spider beetles due to the likelihood rative Indian corn, and nuts. exposed. Legs are reddish. of these food sources. As infestations become severe, beetles will crawl and Bean Weevil With beans stored indoors at warm emerge from walls between floors, (Acanthoscelides obtectus) temperatures, bean weevils breed attics, basements, and crawl spaces. continuously as long as there is food The most common pest of stored When associated with an animal in- left in the beans. Populations can festation, removal of animal wastes is legumes, such as beans, cowpeas, become very high. and peas in Nebraska is the common an essential component of managing spider beetles. bean weevil (Figure 9-11). The bean Spider Beetles (Family: Ptinidae) Spider beetles (Figure 9-12) get their Grain Mites (Acarus siro) name because many actually resem- The grain mites (Figure 9-13) are ble small spiders in appearance with pests of food and feed products, their small head, prothorax and large like cereals, dried vegetable materi- globular-shaped abdomen. With a als, cheese, corn and dried fruits. quick glance, their six long legs and These mites proliferate under high two long antennae look like the eight

Photo: Kansas State University Photo: Kansas legs of a spider. Figure 9-11. Bean Weevil - Adult Adults vary in size from 1/8 to weevil is not a true weevil, like the 1/4-inch long, are reddish-brown granary and rice weevils, discussed to black. Females lay eggs within earlier. They are members of the the food mass, such as grain, seeds, closely related seed beetle family. cereals, dried fruits, meats, wool and Photo: of Idaho University Their body shape is more round than hair. Mature larvae are approximately Figure 9-13. Grain Mites the rice and granary weevils, and they Adults, Immatures, and Eggs do not have the slender protruding snout of these true weevils. moisture conditions and are often found in conjunction with fungal Bean weevils are common in the field. growth. Severe infestations result in Sometimes, gardeners harvest beans brownish tinge over the commodity, from the garden that look perfectly called “mite dust” because of the light good but can be infested. People may brown coloring of the mite legs. This notice bean weevils for the first time Photo: UNL Dept. of Entomology “mite dust” gives off a “minty” odor if on windows and doors as they emerge Figure 9-12. Spider Beetle - Adults the mites are crushed.

92 • IPM for Fabric and Pantry Pests © The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. The life cycle from egg to adult takes The following tips may be useful. Vacuuming picks up hiding insects only about two weeks at normal and spilled or infested material. room temperatures. Overcrowding • Purchase food in package sizes Empty the vacuum cleaner or discard in heavily infested products will force that can be used up in a short the vacuum cleaner bag after use to mites to move off in search of other time. Do not store food products prevent reinfestation. food sources. more than two to four months, if possible. Use older packages Do not use insecticides for control- Damage before newer ones and opened ling these or other insects in pantry packages before unopened ones. areas. Washing shelves with deter- Several stages (egg, larva, pupa and gent, bleach, ammonia or disinfec- adult) of these insects may be present • When purchasing packaged foods, tants will not have any effect on these at the same time in infested prod- be certain containers are not dam- pests since these insects lay their eggs ucts. Since we keep our buildings aged, and seals are intact. on suitable food. Removing infested warm, these insects may continually items and thoroughly cleaning with reproduce and many stored product • Store dried foods in insect-proof a vacuum is usually sufficient. As a infestations can be found nearly any containers such as screw-top glass, precaution against reinfestation, store time of the year. heavy plastic or metal containers. susceptible foods in tightly sealed This will prevent entry or escape glass, metal or heavy plastic contain- The first indication of an infestation of insects. Cardboard, paper or ers or in the refrigerator or freezer. is often presence of small brown plastic wrapping will not prevent If insects continue to appear, go beetles, moths, or worms in storage insect infestations. areas or on counters. Upon closer through stored items again and also inspection, insects may also be found check other rooms in the building for • Keep food storage areas clean and possible sources. Tree seeds blown in opened packages or containers of do not allow crumbs or food par- food and in the cracks and crevices into ventilators or around windows ticles to accumulate, as exposed may harbor these pests. If insect of shelves. Unopened packages may food will attract insects. Cleanli- also become infested because some problems persist, seek assistance from ness is especially important in ar- a pest management professional. of these insects can readily chew into eas where pet foods and birdseed cardboard and foil packaging. Insects are stored. Resources can be brought into the facility along with infested food products. They can Management Options For management practices and multiply and spread to other stored pesticide recommendations on foods. Inspection and identification of all fabric and pantry pest control, see potential food sources is essential to the publications available from UNL Prevention controlling the infestation. Control Extension on-line at: http://www. requires locating and discarding all ianrpubs.unl.edu. Once a pantry pest infestation is infested items. Do not overlook intact Educational resource guides on suspected, identify the pest and try boxes or containers because many to locate the source. Occasionally, the pantry and fabric pests are available insects can chew their way into card- at: http://lancaster.unl.edu/pest/ source of an infestation can be very board and foil. hard to find. It may be in an un- resources/pantrypests304.shtml. opened package. Consider the possi- Infested items can be thrown away bility that food may have been spilled or salvaged by freezing three to four next to or behind hard-to-move days. Food can be heated in a 140ºF appliances. Mice will sometimes col- oven for an hour with the same lect seeds or dry pet food and hoard result. You should empty and thor- them in walls, under cupboards or oughly vacuum cupboards or shelves dishwashers where the infestations holding infested items. Pay particu- are nearly impossible to find. lar attention to cracks and corners.