Common stored product pest species

Stored Product Pests covers a large variety of insects, including beetles and moths.

Learn more below about common species of Stored Product Insects (SPIs) found in the U.S.

Almond moth

(Cadra cautella)

The Almond Moth goes by the nicknames “Cocoa Moth” and “Tropical Warehouse Moth”. The almond moth infests stored products and the adults can fly.

A sign of infestation in the product is contamination with silk webbing, frass, cast skins, pupal cases and adult remains.

Almond moth

Appearance

  • The body is 7.5 – 10 mm long.
  • The adult almond moth has a wing span of 19 mm.
  • The forewings are grey to dusty brown.
  • The larvae is white to pink in color and has a distinctive brown head
  • There is a dark straight band across the forewing, which is paler on the inner edge.

Lifecycle

  • The female lays 150 - 200 eggs loosely and randomly on a food source.
  • The larva can grow to 12.7 mm in length.
  • When the larva is mature, it will actively leave the food source and search for a site in which to pupate.
  • The larva pupates in a silk cocoon.

Habits

  • The almond moth is found worldwide in processing facilities, warehouses and households.
  • It feeds on grain, cereal products, oilseeds and dried plant products, like nuts, fruit and tobacco.
  • The larva burrows into food and creates silk tunnels in which it will be concealed while feeding.
  • Large larva can burrow through packing

Australian spider beetle

(Ptinus tectus)

Australian Spider Beetle Image

Appearance

Covered in brown and golden hairs, the Australian spider beetle has a spider-life appearance and adults grow to an approximate 2.4 – 4mm in length.

Lifecycle

Australian spider beetles live for up to 3 – 4 months at 20 - 25°C.

Feeding Habits

Larvae are often found feeding on miscellaneous debris, and the Australia spider beetle possesses the ability to bore into various inedible materials prior to pupation. Active in dark, damp places, the Australian spider beetle is often associated with bird nests.

Bean weevil

(Acanthoscelides obtectus)

Bean weevil

Appearance

  • 2.0 – 3.0mm long, mottled brown in color. 
  • They have a ‘tear drop’ like body shape and are covered in short hairs. 
  • Saw-tooth like antennae and elytra that do not cover the entire abdomen.

Lifecycle

  • Lifecycle usually lasts 2-4 months.
  • The larvae feed within the beans as they mature. 
  • The larval stage can take from a few weeks to many months to complete, depending upon temperature and moisture of the bean. Pupation is within the bean. Circular holes are cut for the adult to emerge. 
  • Development and breeding goes on as long as there is any food left in the bean and the temperature is right (warmer temperatures are preferred).

Habits

  • Larvae feed mostly inside beans.
  • These weevils attack all legumes, including kidney beans, green beans, peas and lentils. 
  • Heavily infested peas are often reduced to shells.

Biscuit beetle

(Stegobium paniceum)

Biscuit beetle

Appearance

  • Adult — 1/16" - 1/8 in length. Humped thorax. Fine hairs cover the body. Elytra (wing cases) have ridges with indentations. 
  • Larva — active in early stages of development. Bores into hard substances. 
  • They are able to detoxify some poisonous substances.

Lifecycle

  • Life cycle — 200 days at 17°C, 70 days at 28°C. Adults live for 13 to 65 days.

Habits

  • Will often fly. Adults do not feed.

Booklice

(Various species - Liposcelis bostrychophila, Lepinotus patruelis)

book louse

Appearance

  • Adult — Size varies according to species. 1/16" - 1/8" long. Pale yellow–brown to dark brown in color. 
  • Nymphs — very small, often appear transparent. No larval stages.

Lifecycle

  • Liposcelis bostrychophila — prefers high temperatures 77-86°F.
  • Lepinotus patruelis — will breed at 40-60°F.

Habits

  • Liposcelis bostrychophila — Common in homes. 
  • Lepinotus patruelis — Common in factories and on pallets.

Broadhorned flour beetle

(Gnatocerus cornutus)

Broadhorned Flour Beetle Gnatocerus Cornutus

Appearance

An approximate 3.5 – 4.5mm in length, male broadhorned beetles have two enlarged mandibles on the head, giving the appearance of horns and thus their name. Females are very similar in appearance to the confused flour beetle.

Lifecycle

With temperature limits of 60-90°F, broadhorned flour beetles cannot complete their life cycle below 50°F.

Feeding Habits

Feeds on flour, dough, semolina etc. Moth eggs and larvae may supplement the broadhorned flour beetle diet.

Cheese mites

Cheese Mite

Appearance

Cheese mites have soft, hairy cream white bodies with 8 hairless legs and adults grow up to an approximate 0.5mm in length.

Lifecycle

The cheese mite favors warm, moist conditions and eggs mature in 10 days at room temperatures. Females can lay up to 900 eggs in a lifetime at a rate of 20 – 30 a day. Adult cheese mites can live for up to 60 – 70 days.

Feeding habits

With a preference for old cheese to young cheese, these mites also feed on nuts, dried eggs, fruit, flour and tobacco. Cheese mites are capable of contaminating foods to cause skin or gut irritation.

Cigarette beetle

(Lasioderma serricorne)

The Cigarette beetle is a very common commercial pest.

Cigarette Beetle Lasioderma Serricorne

Appearance

  • The Cigarette Beetle is about 2-4mm in length.
  • The adult is whitish in color, with the head dark brown to tan, and are densely haired.
  • The cigarette beetle closely resembles the drugstore beetle.
  • The cigarette beetle has the head bent down nearly at right angles to the body giving it a humped back appearance when viewed from the side.
  • The larvae are about 4 mm long and somewhat bent.

Lifecycle

  • The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 10-100 eggs.
  • The eggs are laid loosely on the infested material.
  • The larval period usually ranges from four to five months, but under very favorable conditions the development from egg to adult may occur in 6 to 8 weeks.
  • When the larvae are fully grown, pupation occurs and they remain in this resting stage for 12 to 18 days.

Habits

  • The Cigarette Beetle feeds off tobacco, dry stored food products, spices, seeds, grains and dried plant material.
  • They have also been reported in rice, dried potatoes, paprika, raisins, grain-based mouse bait and dried straw flowers.
  • Adult beetles often wander away from infested materials and may be found throughout the area.

Coffee bean weevil

(Araecerus fasciculatus)
Coffee bean weevil

Appearance

  • Adults: 1.5-4mm in length. 
  • It is a dark brown beetle with light brown spots and long antennae. 
  • The footless, slim larvae are curved and hairy and grow to a length of 5-6mm.

Lifecycle

  • The beetle flies to fields and lays its eggs on damaged cobs. 
  • The larvae bore into coffee beans in which they pupate.

Habits

  • They mainly infest corn, cocoa, coffee beans, dried fruits, nutmegs, ginger etc.

Confused flour beetle

(Tribolium confusum)

The confused flour beetle was named because of the confusion over its identity. It is a very common commercial and pantry pest.

Confused Flour Beetle Image

Appearance

  • The confused flour beetle is 3-4 mm in length, the larvae are about 6 mm long.
  • The adult is red-brown in color and the larvae are a light honey color and about.
  • It resembles the rust-red flour beetle, except for the antennae which is four segmented and gradually thickens towards the tip - another slight difference is in the shape of the thorax.
  • The sides of the rust-red flour beetle are curved, whereas the thorax of the confused flour beetle is straighter. It has well developed wings but seldom flies.

Lifecycle

  • Female lays between 400 - 500 eggs, with peak oviposition occurring during the first week.
  • Adults may live longer than 3 years, and females may lay eggs for more than a year.
  • Eggs are deposited directly in flour, other food material, or attached to the surface of the container. They are white or colorless and covered by a sticky material to which flour can adhere.
  • Eggs hatch in 3 - 5 days at 90-95°F. Larvae burrow into kernels of grain but may leave their burrows in search of a more favorable food.

Habits

  • Feeds off grain, flour, and other cereal products, beans, cacao, cottonseed, shelled nuts, dried fruit, dried vegetables, drugs, spices, chocolate, dried milk and animal hides.
  • They cannot feed on whole grain, but can feed on broken kernels that are usually present.

Copra beetle/Red legged ham beetle

(Necrobia rufipes)
Copra beetle

Appearance

  • Adults: 3/16" in length. 
  • The upper surfaces of the body are a shiny metallic bluish-green. The underside of the abdomen is dark blue. Their legs are bright reddish-brown or orange. The antennae are reddish–brown with a dark brown or black club at the tip.

Lifecycle

  • Females lay up to 30 eggs per day in cracks or crevices of cured fish. The eggs take between four and six days to hatch. 
  • The larvae will grow for 30 to 140 days, become less active and look for a dark place to pupate. 
  • The pupal stage varies between 6 and 21 days. 
  • An adult will mate soon after emerging from its pupal stage and can live for up to 14 months.

Habits

  • The adults fly and can therefore easily disperse to new sources of food. 
  • They are destructive in both the larval and adult stages, although the larval stage is the most destructive. 
  • They are also cannibalistic, preying on their own eggs and pupae.

Dermestes beetle

(Dermestes beetle)

dermestes beetle

Appearance

  • Adult – 1/4"–3/8" in length. Black with a whitish band across the fore–part of the elytra. 
  • Larva – comet shape. Quick moving. Brown in color and hairy. Migrate to pupate in solid material.

Lifecycle

  • 2–3 months at 64–77°F.

Habits

  • Feeds on various animal products including cheese.

Drugstore beetle

(Stegobium paniceum)

The drugstore beetle (also known as the Biscuit Beetle) gained its name because it was frequently found feeding on drugs in pharmacies many years ago. Now, they are customarily found infesting all types of dry stored food products, spices, seeds, grains and dried plant material.

Biscuit Beetle Stegobium Paniceum

Appearance

  • Approx. 3 - 4 mm long, red-brown, oval beetles.
  • The larvae are small and white approximately 0.5 mm long.
  • The drugstore beetle is a red-brown oval-shaped beetle.

Lifecycle

  • The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 20-100 eggs.
  • The hatching larvae are 0.5 mm long and very mobile.
  • The larval period usually ranges from four to five months, but under favorable conditions the development from egg to adult may occur in 6 to 8 weeks.
  • When the larvae are fully grown, pupation occurs and they remain in this resting stage for 12 to 18 days.

Habits

  • It is not a major pest in stored grains but will attack spices, seeds, grains and dried plant material as well as packaging materials such as paper and cardboard.
  • They have also been known to feed on leather, wool, hair and books.
  • Their presence can be detected from pinhead holes in the infested items.
  • Packaging materials such as paper and cardboard are also attacked.
  • Since the drugstore beetle can fly well, the source of infestation can sometimes be hard to find.
  • The drugstore beetle is not a major pest in stored grains.

Flat grain beetle

(Cryptolestes ferrugineus)
Flat grain beetle

Appearance

  • Adult — About 1/8" in length. Flattened body with very long antennae. Light red to dark reddish brown. 
  • Larva — yellowish–white. 0.5mm long growing to 4mm when mature.

Lifecycle

  • Prefers warm damp conditions. 69–103 days at 70°F, 26 days at 100°F.

Habits

  • Adults are winged but rarely fly. 
  • Feeds on cereals, dates, dried fruits and other commodities.

Flour mite/Grain mite

(Acarus siro)
Flour mite

Appearance

  • Adult — 0.5 mm long. 4 pairs of legs. White or pale brown. Slow moving. 
  • Larva — 6 legged and 0.5 mm long. White in color. Passes through two, 8 legged nymphal stages.

Lifecycle

  • 9–11 days at 73°F and 90% relative humidity.

Habits

  • Under adverse conditions, may pass through a long and very resistant stage called a hypopus.

Fur beetle

(Attagenus pellio)

Fur beetle

Appearance

  • Adult — 3/16"–1/4" long. Elongate oval. One small patch of white on each wing case, otherwise red–brown to black. 
  • Larva — 1/4" long. Long orange tufts of hair on the last abdominal segment. 
  • Larvae have a banded appearance. 
  • Pupa — formed in the last larval skin.

Lifecycle

  • Mating takes place outdoors after which they fly indoors to lay eggs. Normally one generation per year but development may extend to three years.

Habits

  • A common inhabitant of birds nests. Adults feed outdoors often on Spiraea plants. 
  • Larvae attack furs, skins, woollens, etc. and stored grain.

Furniture mite

(Glycyphagus domesticus)

Furniture mite

Appearance

  • Adult – 0.3–0.7mm. Hairy soft cream–white body with yellow/brown legs.

Lifecycle

  • Egg to adult in 22 days at room temperature. 
  • Adult lives for approximately 50 days.

Habits

  • Capable of tainting foods and causing gut irritation. 
  • Commonly feeds on flour, cereals and fungi. 
  • Favours moist environmental conditions; common in damp poorly ventilated rooms.

Golden spider beetle

(Niptus hololeucus)

golden spider beetle

Appearance

  • Adult — 1/8" - 3/16" in length. Ovoid abdomen with a pinched waist. Whole body covered in golden-yellow hairs. 
  • Larva — similar to Australian spider beetle.

Lifecycle

  • 6 - 7 months at 68°F. Adults can live up to 9 months.

Habits

  • Sometimes linked to the damage of textiles in the domestic home. 
  • Adults appear in greater numbers in June/July and October/November.

Grain borer

(Prostephanus truncatus)

Grain borer

Appearance

  • Brown body color. 1/16" to 3/16" in length. 
  • Antennae have 3 large segments at the end forming visible antenna clubs, reddish in color. 
  • The humped thorax covers the head, its front rim has teeth–like indentations. 
  • Elytra (wing covers) are heavily punctated and drop off sharply at the back, giving the impression of a square end when seen from above.

Lifecycle

  • The female lays an average of 10 eggs on a grain of maize and the hatched larvae bore into the grain. 
  • The larva undergoes up to 4 development phases and pupates inside the corn grain. 
  • Lifecycles can be quite short, in good conditions (25 days at 93°F, 75% relative humidity) there are several generations per year.

Habits

  • Adult beetle is a pest of stored maize, but also infests other types of grain. Larvae bore tubular passages into the grain, typically making one main tunnel with smaller ones branching off. 
  • Brought in from tropical Central America in cassava roots and tapioca products, as well as in starchy fruits and tubers.

Granary weevil

(Sitophilus granarius)

The Granary Weevil is among the most destructive of all stored grain insects. The larvae develop inside kernels of whole grain in storage. This makes an infestation difficult to remove in the milling process.

Granary weevil image

Appearance

  • Dark brown-black in color.
  • It is about 2.5 - 5 mm in length.
  • They possess a long slender snout and cannot fly.
  • In the larval stage the weevils are legless, humpbacked, white to creamy white, with a small, tan head.
  • Weevils in the pupa stage have snouts like the adults.

Lifecycle

  • The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.
  • Emergence holes of the granary weevil are fairly large and tend to be more ragged than smooth and round.
  • Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.
  • The life cycle is about 30 to 40 days during the summer, and 123 to 148 days during the winter, depending on temperature.

Habits

  • Most of their life is spent within the grain kernel.
  • Both larvae and adults feed on grain.
  • Grain weevils will also attack hard cereal products, e.g. macaroni and spaghetti.

Larder beetle

(Dermestes lardarius)

Larder beetle

Appearance

  • Adult — 1/4"–3/8" in length. Black with a whitish band across the fore-part of the elytra. 
  • Larva — comet shape. Quick moving. Brown in color and hairy. Migrate to pupate in solid material.

Lifecycle

  • 2–3 months at 64-77°F.

Habits

  • Feeds on various animal products including cheese.

Leather beetle

(Dermestes maculatus)

leather beetle

Appearance

  • Adult — 1/4"–3/8" in length. Uppermost is black, underside is white. 
  • Larva — as D. lardarius but with an orange stripe running down the length of the back.

Lifecycle

  • 2–3 months at 64-77°F.

Habits

  • Feeds on various animal products and dried fish. Pupates in solid material, e.g. wood. 
  • The quantity of white on the underside may vary according to species. Adults fly readily.

Lesser grain beetle

(Rhyzopertha dominica)

This beetle lives and feeds in warehouses and stores, especially feed and health food stores.

Lesser grain beetle

Appearance

  • The lesser grain borer is black-brown in color.
  • It is about 2.5 - 3 mm long.
  • The body has a slender cylindrical form and the head is hidden under the round neck-shield.
  • The larvae are whitish with a yellow head.

Lifecycle

  • Adult females lay eggs singly or in groups of up to 30.
  • The eggs are laid on the outside of the grain and a female can lay from 300 - 500 eggs.
  • In hot summer conditions it may take as few as 30 days, but the average is about 58 days.
  • Pupation takes place inside the hollow shell of the seed or in the "flour" that accumulates with infested grain.

Habits

  • The lesser grain borer is primarily a pest in stored wheat and corn.
  • It can infest tobacco, nuts, beans, bird seed, biscuits, cassava, cocoa beans, dried fruit, peanuts, spices, rodenticide baits, and dried meat and fish.

Lesser mealworm

(Alphitobius diaperinus)

Lesser meal worm

Appearance

  • Adults - 1/4" long. Newly moulted adults are reddish-brown turning black. 
  • Larvae - 5/16" long. Slender, segmented and worm-like with three pairs of tiny legs on the thorax and one abdominal proleg at the rear.

Lifecycle

  • Females can lay up to at least 110 eggs a month and eggs hatch in 4-7 days. Larval development takes up to 7 weeks. Mature larvae seek a sheltered place to pupate for between 7 and 11 days. 
  • An adult beetle may live up to two years.

Habits

  • The beetles are attracted to poultry operations, which have ideal conditions for their development. The damage to insulation is carried out by lesser mealworms seeking a safe place to pupate because the darkling beetles prey on the lesser mealworms.

Maize weevil

(Sitophilus zaemais)

Also known as the Greater Rice Weevil. Maize Weevils are frequently regarded as primary pests of grain since they are able to infest otherwise undamaged grain.

They have also been seen to infest buckwheat, peas, acorns, chestnuts and cottonseed.

maize weavil

Appearance

  • It is about 2.5 - 4 mm long.
  • The head has a long slender snout.
  • Resembles rice weevil, only bigger and the red-brown spots on wing covers are more clearly marked.
  • It is a stronger flier than the rice weevil.

Lifecycle

  • The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.
  • Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.
  • The egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there.
  • New adults bore emergence holes from the inside, then leave to mate and begin a new generation.

Habits

  • Both larvae and adults will feed upon grain.
  • Weevil-damaged grain can be readily recognized by the presence of large holes which are the exit holes of the emerging adults.

Mediterranean flour moth

(Ephestia kuhniella)

The Mediterranean flour moth larva is a very common commercial and pantry pest. It is a pest of mills and warehouses as it can clog machinery with its webs.

Larder Beetle Image

Appearance

  • Mediterranean Flour Moth adult has wingspread of about 20 – 22mm and when at rest it is 10 - 14 mm long.
  • The hind wings are dirty white while the forewings are blue-grey with transverse dark wavy bars and a row of dark spots at the tip.
  • The larvae are white in color with a brown head and neck shield.
  • The larvae can take on a pinkish or greenish hue and can reach a length of 15 - 20 mm.
  • The pupa form a brown, spindle shaped cocoon approximately 9 mm.

Lifecycle

  • The female lays between 100 - 700 eggs (usually 200) in and among the food source and usually fastens the eggs to the infested material.
  • The eggs usually hatch in 3 - 5 days and the hatching larvae produce a lot of webbing.
  • The young larvae confine themselves to silken tubes which are constantly spun.
  • The larva attains full size in around 40 days. The larva pupates in or on top of the infested material (usually flour) or in cracks and crevices nearby.
  • The life cycle can be completed in as few as 4 - 6 weeks but usually takes about 3 months.

Habits

  • The Mediterranean flour moth is mostly found infesting flour and meal.
  • It has also been found infesting grain, bran, cereal products, nuts, chocolate, seeds, beans, biscuits, dried fruits and other stored foods.

Rice weevil

(Sitophilus oryzae)

Rice weevils are pests of stored grain and seeds.

Rice Weevil Image

Appearance

  • The adult rice weevil is 2.5 - 3.5 mm long and has a slender, hard-shelled bodies that appear pitted or scarred with tiny holes.
  • They are brown-black in color and possess a long slender snout.
  • Rice weevils have four faint red-brown spots on the back of the abdomen.

Lifecycle

  • The adults live 3 to 6 months, infesting grain in the field.
  • The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.
  • Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.
  • The egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there.
  • New adults bore emergence holes from the inside, then leave to mate and begin a new generation.
  • Female rice weevils lay between 300 to 400 eggs, with the life cycle requiring about 32 days for completion. Two larvae can develop in one wheat kernel.

Habits

  • The adults can feign death by drawing up their legs close to the body, falling, and remaining silent when disturbed.
  • Emergence holes of the rice weevil are smaller than those of the granary weevil, and tend to be smooth and round.
  • There is generally no external evidence that the larvae have been eating and growing inside the seed until after about one month when the adult weevil chews through the seed coat and emerges.

Rove beetles

(Paederus riparius)

Rove beetles

Appearance

  • Adult – 5/16"–3/8". Body color is an alternating black and red.

Lifecycle

  • Eggs laid singly on moist substances and typically develop in 3–19 days. 
  • The larvae pass through two stages before reaching adulthood. 
  • Adults are most common in spring and early summer.

Habits

  • They are common in habitats with large numbers of fly larvae (e.g. decaying fruit or seaweed, compost).
  • The larvae and adults are general predators of small insects and other arthropods, including pests of crops.

Rust-red flour beetle

(Tribolium casteneum)

Is a very common commercial pest infesting a variety of grain and food materials. The rust-red flour beetle is frequently found in stored products in the U.S.

Rust red beetle

Appearance

  • The Rust-red flour beetle is red-brown in color.
  • 3.0 - 4.0 5mm in length.
  • The antenna of the rust-red flour beetle is distinctly club-like, with a three segmented club and it has grooved wing covers.
  • The Rust-red flour beetle has well developed wings and has been observed to fly.
  • The larvae are a light honey color and about 6 mm long.
  • The head and a distinctive forked process at the tip of the abdomen are slightly darkened.

Lifecycle

  • The female lays approximately 400 - 500 eggs, with peak oviposition occurring during the first week.
  • Adults may live longer than 3 years, and females may lay eggs for more than a year.
  • Eggs are deposited directly in flour, other food material, or attached to the surface of the container. They are white or colorless and covered by a sticky material to which flour can adhere.
  • Eggs hatch in 3 - 5 days at 90-95°F. Larvae burrow into kernels of grain but may leave their burrows in search of a more favorable food.
  • Larvae are fairly active but generally hide within the food, away from light.
  • Development time from egg to adult varies with conditions, however the average is 26 days at 90-95°F and >70% relative humidity (R/H).

Habits

  • When agitated or crowded, they may secrete chemicals called quinones. These chemicals can cause the infested feed to turn pink and have a pungent odor.
  • They have been reported in grain, flour, and other cereal products, beans, cacao, cottonseed, shelled nuts, dried fruit, dried vegetables, drugs, spices, chocolate, dried milk and animal hides.
  • They cannot feed on whole grain, but can feed on broken kernels that are usually present.
  • In general, fungi may play a significant role in the nutrition of rust-red flour beetles.

Saw toothed grain beetle

(Oryzaephilus surinamensis)

The saw-toothed grain beetle is one of the most common insects in stored grain and cereal products

Saw Toothed Grain Beetle Image

Appearance

  • Adult is brown and is approximately 3 mm.
  • Mature larva is yellowish white.
  • Adult has a flattened body.
  • Wings are present, developed, but they do cannot fly.

Life Cycle

  • The female lays eggs singly or in small batches in the food product. She lays about 200 eggs in her lifetime.
  • Eggs hatch after about 8 days.
  • The life cycle takes about 35 days and the larvae feed in the top few centimetres of the food stuff.
  • Adults usually live around 6 to 10 months.

Feeding Habits

  • The larvae develop in flour, cereal products, and many other dried foods, including grains, cereals, bread, pasta products, dried meat, dried fruit and nuts, sugar, chocolate, candy, tobacco products and drugs.
  • A common pest not only in grain bins, but also, mills, processing plants, warehouses, and kitchens.
  • In grain bins, it feeds on broken kernels and grain residues.
  • The beetles can chew through sealed packaging such as cardboard boxes, plastic bags and foil wrappings.

Shiny spider beetle

(Gibbium psylloides)

shiny spider beetle

Appearance

  • Adult – 1/32"-1/8" long. They are shiny red-brown to black. The body is hairless, and lacks the general spider beetles characteristic restriction at the waist.

Lifecycle

  • Females lay up to 120 eggs either singly or in batches during early summer. The eggs hatch within 16 days, and remain in the larval stage for up to 6 weeks. 
  • Adults emerge after 20-30 days of the pupal stage and may live for up to 12 months. 
  • At the optimum temperature for development (91°F) it takes about 45 days for the life cycle to be complete.

Habits

  • Shiny spider beetles are tolerant of cool conditions and can stay alive for long periods without food. 
  • If disturbed, they will act as if dead.

Warehouse beetle

(Trogoderma variabile)

Warehouse beetle

Appearance

  • 1.5-4.0mm long, and oval in shape. 
  • Mostly dark brown in color, with mottled lighter brown markings.

Lifecycle

  • Lifecycle usually lasts between 1.5-6 months. 
  • The larva is up to 10mm long, and pale cream with indistinct dark brown markings. 
  • The larva has 3 pairs of legs and is very bristly.

Habits

  • This pest has recently been introduced into the U.S. 
  • May be found in many organic materials such as seeds, grains, most types of packaged foods, snail baits, dog biscuits, stock feeds, old rodent baits, grain remnants in sacks, bee and wasp nests, rodent carcasses, dead insects, animal droppings etc. 
  • The hairs dropped by larvae may cause human problems such as asthma, skin problems or gastric disorders.

White marked spider beetle

(Ptinus fur)

White marked spider beetle

Appearance

  • Adult, 1/16"-3/16" long, red-brown with yellow hairs; prothorax with dense cushion of pale hairs on each side. 
  • Wing cases (elytra) have white scales.

Lifecycle

  • 3 - 4 months at 68-77°F.

Habits

  • Will feign death if disturbed. Active in dark, damp places. Often linked to birds nests.

Yellow mealworm beetle

(Tenebrio molitor)

Yellow Mealworm Beetle Image

Appearance

  • Adults – 3/4" long. They are shiny, dark–brown or black. 
  • Larvae are honey–yellow, they have a smooth, highly polished, shiny, elongate, hard, worm-like body, and can grow to 1 3/16" long.

Lifecycle

  • Each female lays about 275–600 eggs singly or in clusters during the spring. 
  • They are white, bean-shaped and about 1/32" long and hatch into larvae in 4 to 14 days. 
  • The pupal stage lasts 7 to 24 days during the spring. Pupae are first white, turning yellow, and are not enclosed in a cocoon. 
  • Adults emerge in the spring or early summer, living for two to three months.

Habits

  • They are highly resistant to cold temperatures. 
  • It is an important post–harvest pest and occurs spread all over the world. 
  • Adult beetles are attracted to night-lights, are strong fliers, and are found in dark places.

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