7A Ch8 Cheat Sheet: Stored-Product & Fabric Pests

🎯 Top 5 Traps

1

Hide and larder beetles do NOT eat fabric or grain — they eat MEAT, FLESH, and LEATHER. Even though they belong to the same family (Dermestidae) as carpet beetles, larvae of hide and larder beetles feed on bird and mammal flesh, cured meats (ham), and leather. Often found infesting dead birds in chimneys/wall voids or mice in traps. The hide beetle is even used in museums to clean vertebrate skeletons.

2

Carpet beetle LARVAE — not adults — cause most textile damage. Adult carpet beetles commonly feed on flowers and flower pollen. The larvae do the damage to woolens, furs, feathers, and tapestries. When food is scarce, larvae continue to molt for longer periods, waiting out the food supply — they can be very long-lived.

3

Clothes moths CANNOT live on CLEANED wool — they depend on STAINED wool, fur, silk, and feathers. They need certain vitamins produced by microorganisms growing on sweat, food, or urine stains. Without those vitamins, clothes moth larvae die. This drives the entire fabric-pest control strategy: dry-clean infested clothing — dry cleaning kills all stages.

4

Clothes moths NEVER fly to lights — they are secretive and remain in dark areas (or do not fly at all). They scuttle down into dark folds of textiles or fur. This is a clear distinction from Indian meal moth, which DOES fly visibly indoors and can wander long distances (room to ceiling, between floors). If you see a moth flying around a light, it is not a clothes moth.

5

Naphthalene gives LONGER protection than PDB (paradichlorobenzene) — naphthalene is LESS volatile. PDB crystals vaporize much faster and must be maintained to ensure protection. Both are sold as mothballs/moth crystals in department stores. Use only amounts recommended on the label, in tight chests where vapors and odor will not be breathed by occupants.

🔢 Numbers You Must Know

Number

What It Represents

2 months

Indian meal moth life cycle

1/3 inch

Indian meal moth adult length (longer with wings folded backward)

1/2 inch

Indian meal moth larva length (cream-colored, sometimes pinkish/greenish, with brown heads)

Less than 1/8 inch

Saw-toothed grain beetle (3 ridges on top of thorax with 6 fine teeth on EACH side — key ID)

1/16 to 1/4 inch

Cabinet/warehouse beetles (Trogoderma) — oval; black with 3 reddish-brown, golden, or gray irregular lines

1/8 inch

Cigarette and drugstore beetles (oval, reddish brown), and red and confused flour beetles

1/4 to 3/8 inch

Larder beetle and hide beetle (the LARGE Dermestes species)

1/8 inch (adult)

Black carpet beetle adult — oblong to oval, dark brown or black, not shiny

1/4 to 1/2 inch (larva)

Black carpet beetle larva — carrot-shaped, dark brown to golden-red hair, twisted tuft at tail

1/4 to 1/3 inch

Webbing and case-making clothes moths (body length at rest); wingspan less than 1/2 inch tip-to-tip

3 dark spots

On EACH front wing of the case-making clothes moth (head + front wings dusty brown or tan); webbing moth has plain golden buff wings with no spots

1/16 inch

Psocid ("book lice") length — pale gray or yellowish white, wingless, soft-bodied

At least 60 percent

Minimum relative humidity required by psocids (also promotes the mold/fungal growth on which they feed)

75 to 85 percent

Preferred relative humidity range for grain mites (Acaras siro)

🔀 Easily Confused

Pair / Group

Distinguishing Feature

Primary vs Secondary stored-product pests

Primary: chew through intact seed coats — rice/granary weevils, Angoumois grain moth, lesser grain borer, seed beetles (Bruchidae). Secondary ("bran bugs"): infest products with seed coats already broken or removed — Indian meal moth, saw-toothed, cabinet/warehouse, cigarette/drugstore, flour beetles, spider beetles.

Rice weevil vs Granary weevil

Two similar snout beetles found in stored whole grains. Rice weevil: common in southern states, CAN FLY. Granary weevil: more common in cooler climates, CANNOT fly. Both deposit eggs inside grains; larvae devour the inside.

Indian meal moth larva vs Clothes moth larva

Indian meal moth larva: 1/2 inch, wanders OPENLY long distances (lower levels through holes to upper areas, pantry to ceiling, dangles from ceiling on silk strands). Clothes moth larva: tiny, does NOT wander openly. Numbers + wandering + size easily distinguish them.

Cigarette beetle vs Drugstore beetle

Both 1/8 inch oval reddish brown, both can fly, both related to powderpost beetles. Cigarette beetle: covered with tiny hairs giving GOLDEN SHEEN. Drugstore beetle: appears DULL and DARKER because of deeper lines on its wing covers. Both favor spices (paprika!), milled cereals, dry dog food.

Hide/larder beetles vs Other dermestids (carpet/cabinet beetles)

All in family Dermestidae. Hide and larder beetles (Dermestes): eat FLESH (dead birds, mice, cured meats) and leather — NOT typically fabrics or grain. Black/common/furniture/varied carpet beetles (Attagenus, Anthrenus): infest woolens, furs, feathers. Cabinet/warehouse beetles (Trogoderma): infest grain-based products.

Webbing vs Case-making clothes moth

Webbing (Tineola bisselliella): golden buff head + front wings (NO spots); larvae spin fine SILK over the area of infestation; fecal pellets, pupal cases, cast head capsules catch in silk = messy accumulation. Case-making (Tinea pellionella): dusty brown/tan head + front wings with 3 SMALL DARK SPOTS on each front wing; larvae build a SILKEN CASE that incorporates strands of the infested material — case color matches the infested material.

Psocids vs Grain mites

Both moisture-dependent moldy-grain pests. Psocids ("book lice"): tiny insects, ~1/16 inch, pale, wingless; need at least 60% RH; feed on mold on starchy materials. Grain mites (Acaras siro): tick relatives, dust-like brownish tinge; need 75-85% RH; cast skins pile up like fluffy balls. Mites cause allergies similar to house dust mites.

Naphthalene vs PDB (paradichlorobenzene)

Both sold as mothballs/moth crystals. Naphthalene: LESS volatile, gives LONGER protection in tight chests — preferred for long-term storage. PDB: vaporizes much FASTER, must be maintained to ensure protection. Use only labeled amounts; do not allow continued breathing of either.

Khapra beetle (special note)

A Trogoderma species — VERY serious grain pest. Routine FEDERAL QUARANTINE inspections to prevent its entry and establishment in the United States. Has been known to build up in large infestations.

🌾 Stored-Product Pest ID Quick Reference

PRIMARY PESTS (chew through intact seed coats — whole grains/seeds)

Species

Size / Key ID

Foods / Behavior

Rice weevil + Granary weevil

Snout beetles with mandibles at tip of snout. RICE = can fly (south); GRANARY = cannot fly (cooler climates).

Stored whole grains, cereal grains, seeds. Female chews hole in grain, deposits eggs; larvae devour the inside. More common in granaries/mills.

Angoumois grain moth

Buff/tan/golden moth; 1/2 inch wing span; more than 1/4 inch long with wings folded.

Most commonly in WHOLE CORN (south and midwest). Larger than common golden-colored clothes moth.

Lesser grain borer

1/8 inch cylindrical brown beetle; strong jaws chew through seed coats.

Mainly a problem of stored grain in TRANSPORT (trains, ships). Rarely a problem in urban homes/stores.

Seed beetles / pea & bean weevils (Bruchidae)

1/8 to less than 1/4 inch; broad; light + dark markings. NOT true weevils — no snout.

Infest LEGUME seeds ONLY: peas, cowpeas, beans (incl. mung). Each species specializes in one kind of seed. Larvae bore inside, exit through 1/8-inch holes.

SECONDARY PESTS ("bran bugs" — infest milled, ground, or processed products)

Species

Size / Key ID

Foods / Behavior

Indian meal moth

1/3 inch; gray basal half + COPPERY last half of wings with dark bands; larvae 1/2 inch, cream-colored with brown heads + sparse hairs.

Milled cereals, crackers, cake mixes, pasta, dog food, NUTMEATS (pecans, walnuts), powdered milk, spices, dried fruit. Larvae spin SILK on top of products and dangle from ceilings on silk strands. PHEROMONE TRAPS very effective.

Saw-toothed grain beetle

Less than 1/8 inch; tiny slender dark brown; 3 RIDGES on top of thorax with 6 FINE TEETH on each side.

Same materials as Indian meal moth. Larvae do not leave infested material; adults wander conspicuously. Cockroach bait stations with grain base may attract and kill these beetles.

Cabinet/warehouse beetles (Trogoderma)

1/16 to 1/4 inch; oval (about half as wide as long); base color black with 3 reddish-brown/golden/gray lines.

High-protein cereal: cereal, spices, rodent bait, dry dog food, wheat germ. KHAPRA beetle is a Trogoderma species under federal quarantine.

Cigarette + Drugstore beetles

1/8 inch oval reddish brown; can FLY. Cigarette = golden sheen from hairs; drugstore = duller/darker with deeper wing-cover lines.

SPICES (especially PAPRIKA, ground pepper, ginger), milled cereals, dry dog food, cosmetics, drugs, dried flowers (through glue at flower head).

Flour beetles (red + confused)

1/8 inch reddish brown; short stout antennae. Larvae slightly LONGER than adults; creamy white with few hairs.

Dry milled cereal: flour, cornmeal, cake mixes. Live on flour spills. Common in flour mills, retail stores, homes.

Spider beetles

Less than 1/8 to nearly 1/4 inch; oval; long legs and antennae; abdomen MUCH LARGER than head + thorax. Some shiny + globular look like spiders.

Wide range: flour, broken cereal grains, fish meal, seeds, spices, dried fruit, dog biscuits. In museums: skins, hair, wool, feathers, textiles, insect specimens, leather goods. Use STICKY TRAPS or cockroach monitors.

PESTS OF MOLDY/DAMP/OUT-OF-CONDITION GRAIN

Species

Size / Key ID

Habitat / Control

Psocids ("book lice")

1/16 inch; pale gray or yellowish white; wingless; soft-bodied.

Need at least 60% relative humidity. Feed on MOLD on decomposing starchy materials. Found on books/papers sized with starch in damp situations. Discard the starchy mold source and dry out the area.

Grain mites (Acaras siro)

Tick relatives; dust-like, slightly brownish tinge; almost colorless with long microscopic hairs; cast skins pile up like fluffy balls.

Need 75 to 85% relative humidity. Cause allergies similar to house dust mites. Use tannic acid (carpet cleaners or brewed tea) on cast skins to suppress allergy. Discard infested material and dry out chamber.

🧥 Fabric Pest ID Quick Reference

Fabric pests target KERATIN — the protein in wool, fur, hair, feathers, skins, horns, hooves. Insects are the only animals capable of digesting keratin.

CARPET BEETLES (Dermestidae family)

Species

Size / Key ID

Diet / Behavior

Larder beetle (Dermestes lardarius)

Large, oblong; 1/4 to 3/8 inch; dull dark/black head + thorax; wing covers HALF DULL YELLOW (front) + BLACK (rear).

Eats FLESH (bird/mammal), cured meats (ham), leather. NOT fabrics. Found in homes, cabins, curing sheds.

Hide beetle (Dermestes maculatus)

Large, oblong; 1/4 to 3/8 inch; dorsal dark brown/black, sometimes WHITE SCALES on margin of thorax; UNDERSURFACE covered with white scales.

Eats FLESH, cured meats, leather. Used in MUSEUMS to clean vertebrate skeletons. Larvae leave a perfectly cleaned skeleton in a pile of fluffy undercoat hair.

Black carpet beetle (Attagenus unicolor)

Adult 1/8 inch; oblong-oval; dark brown/black, NOT shiny. Larva 1/4 to 1/2 inch; CARROT-SHAPED; dark brown to golden-red hair; twisted tuft of hairs at tail.

Stored woolen clothes (suits, uniforms, skirts, blankets, felt, wool yarn). ALSO infests grain in elevators and mills. Adults occasionally fly inside in spring from outside flowers.

Common, Furniture & Varied carpet beetles (Anthrenus spp.)

Adult 1/8 inch or less; mottled with yellow/white/orange/black SMALL FLAT SCALES (visible with hand lens). Larvae less than 1/4 inch; dark hair bristles extending from body.

Woolens, furs, feathers, hair-stuffed antique furniture, woolen carpets, blankets. Destroy insect collections (reduce specimens to piles of fecal pellets).

CLOTHES MOTHS

Species

Size / Key ID

Larval Behavior

Webbing clothes moth (Tineola bisselliella)

Body 1/4 to 1/3 inch at rest; wing span less than 1/2 inch. Head + front wings GOLDEN BUFF (no spots).

Larvae spin FINE SILK over the area of infestation. Fecal pellets, pupal cases, and cast head capsules catch in the silk = messy accumulation. Larvae creamy white, 1/4 to less than 1/2 inch, brown head.

Case-making clothes moth (Tinea pellionella)

Same size as webbing moth. Head + front wings DUSTY BROWN or tan with 3 SMALL DARK SPOTS on each front wing.

Larvae build a SILKEN BAG/CASE that covers their abdomen, incorporating tiny strands of the infested material. CASE COLOR INDICATES THE INFESTED MATERIAL. Larva crawls with case attached; pupates inside the case attached to ceiling/wall.

💡 Memory Hooks

Carpet beetle damage: "Larvae do the chewing, adults sip the pollen." Adult carpet beetles feed on flowers; larvae cause all the textile damage.

Hide and larder: "Skeletons, not sweaters." These dermestids eat flesh, cured meat, and leather — NOT fabrics or grain.

Clothes moths and stains: "No stain, no meal." Clothes moths cannot survive on cleaned wool — they need vitamins from microorganisms growing on stains.

Clothes moths and lights: "Dark and quiet, never the light." Clothes moths are secretive and never fly to lights. A moth at the lamp is something else (often Indian meal moth).

Mothballs: "Naphthalene lasts, PDB blasts." Naphthalene is less volatile = longer protection. PDB vaporizes fast and must be replenished.

Humidity thresholds: "Sixty for psocids, seventy-five for mites." Minimum humidity needed for the two main moldy-grain pests to thrive.

Ch.8: Stored-Product & Fabric Pests

🎯 Top 5 Traps

🔢 Numbers You Must Know

🔀 Easily Confused

🌾 Stored-Product Pest ID Quick Reference

🧥 Fabric Pest ID Quick Reference

💡 Memory Hooks