Stored Product Insects

Commonly found in Singapore:

  1. Indian meal moth
  2. Almond moth
  3. Cigarette bettle
  4. Flour beetle
  5. Sawtoothed grain beetle
  6. Foreign grain beetle
  7. Rice weevil

Indian Meal Moth (Plodia interpunctella) – Pantry Moth

General Identification:

  • A mature female lays 100 to 300 eggs on food material.
  • Adult wings generally gray but the rear half of the wings are rusty brown or bronze.
  • Eggs are grayish wish, 0.3 to 0.5 mm.
  • Larvae possess a dark brown head, cream-coloured / yellowish-green / pinkish shades, depending on the food source. They are general feeders, feeding on grain products, dried fruits, pasta, powdered milk, nuts, seeds, chocolate, pet food etc.
  • Pupae are pale brown, 6 to 11 mm long.

Fun Facts:

  • The larvae usually spin a web as they become completely grown and leave behind the siken threads wherever they crawl.
  • Foodstuffs are contaminated with frass, cast skins, pupal cases and dead moths.
  • Large quantities of silk bind together and foul foodstuffs.
  • Active during night time, flying in a zigzag pattern instead of maintaining a direct flight line.
  • At rest, the wings are held roof-like over the body.
  • Adults do not feed and normally rest during the day in shaded areas.
Indian Meal Moth - Website
Almond Moth - Website

Almond moth (Cadra cautella) – Common in warehouses

General Identification:

  • Female moths lay about 200 to 400 small, white eggs on or near to their eventual food source.
  • The adult with a size range from 13 mm to 20 mm.
  • Upper half wing is yellowish-gray with a dark band or stripe at the intersection between two.
  • Webbing present on pupal cases.
  • Feed on a variety of nuts, including almonds, walnuts, peanuts, hazelnuts, dried fruits, grains, seeds etc.

Fun Facts:

  • The larvae create matted webbing during feeding. They pupate in a silk cocoon and they are able to diapause if the conditions are unfavourable for development.
  • Adult moths are seen flying around areas where their food source is stored, more active during dawn and dusk.
  • Foodstuffs are contaminated with frass, cast skins, pupal cases and dead moths.
  • Large quantities of silk bind together and foul foodstuffs.

Cigarette Beetle (Lasioderma serricorne) – Stored product pest that can be found worldwide

General Identification:

  • Infest a wide variety of products such as pet food, flour, cereals, spices and pasta.
  • Adult are shiny, small, stout, yellowish to reddish-brown.
  • Body is round, oval in shape and covered by golden hairs.
  • The head is concealed by the pronotum (bent down) and barely visible from above.
  • Undergo complete metamorphosis.
  • Females lay eggs in or on the food material.
  • The larvae hatched are creamy white and in worm-like shape.
  • Fully-grown larvae pupate in silk-like cocoon covered with materials they have infested.

Fun Facts:

  • Adult cigarette beetles are strong fliers.
  • Active in the late afternoon and on cloudy days.
  • Hide in dark and shaded places during daytime.
  • “Play dead” for a few seconds when disturbed
Cigarette Beetle - Website
Flour Beetle - Website

Flour Beetle – Commonly are confused flour beetle (Tribolium confusum) and red flour beetle (Tribolium castaneum)

General Identification:

  • Known for attacking flour, grain, dried fruits, cereals, nuts, spices.
  • Small, about 3 to 6 mm in length, reddish-brown in colour.
  • Both species of flour beetle are often being confused due to their similar appearance and habit. The antennae of confused flour beetle increase gradually in size and possess four clubs; while antennae of red flour beetle have only three clubs.
  • Can be also found in crevices in pantries and cabinets.
  • Undergo complete metamorphosis.
  • Female adults lay small and white eggs loosely in flour or other material.
  • The larvae are worm-like larvae that are slender and cylindrical.
  • During pupation, the pupae are white, gradually change to yellow and brown.

Fun Facts:

  • Confused flour beetles are named so as they are easily confused with the red flour beetles.
  • Food are contaminated with their feeding damage, dead bodies, fecal pellets.
  • They usually create a pungent smell and cause the growth of mold in food.

Sawtoothed Grain Beetle (Oryzaephilus surinamensis)

General Identification:

  • About 2.5 to 3 mm long.
  • Adults possess 6 saw-like “teeth” on each side of prothorax.
  • Larvae are yellow-white with brown heads, feeding on broken kernels. They create a cocoon from food materials during pupation.
  • Attack grain, cereal, flour, pet food, fruit, chocolate, nuts etc.
  • Their small size allows them to penetrate cracks and crevices in the food packages.

Fun Facts:

  • Do not attract to light.
  • Adults possess wings but do not fly.
  • The tiny saw-like teeth on the prothorax giving them the name sawtoothed beetle.
SAWTOOTHED GRAIN BEETLE - Website
FOREIGN GRAIN BEETLE - Website

Foreign Grain Beetle (Ahasverus advena)

General Identification:

  • About 2 mm long, reddish-brown and three-segmented antennal club.
  • Are scavenger, feeding on fungus or moldy food products.
  • Basically attack food materials, including cereal, flours, grains, nuts, figs etc.
  • Live in damp areas where fungus grows.
  • Larvae are worm-like, cream-coloured.

Fun Facts:

  • Good fliers, manage to gain access through windows.
  • Closely associated with moisture areas which allow fungus or mildew to grow, for example, building with poor ventilation and water leaks.

Rice Weevil (Sitophilus oryzae)

General Identification:

  • Adults about 2 mm long with a long snout, brown or black body.
  • Attack several crops, including wheats, rice, barley, maize, corn, cereals and oats.
  • Female adults bore a small hole into the kernel or seed to lay an egg inside, sealing it with a gelatinous material. The hatched larvae develop and consume within the kernel and eventually hollow it out.

Fun Facts:

  • Strong fliers.
  • Infested grains have exit holes as the adults emerge from the kernels.
  • Adults can live up to 6 months.
Rice Weevil - Website