Species: Rice weevil (Sitophilus oryzae); Granary weevil (Sitophilus granarius); Red flour beetle (Tribolium castaneum); Confused flour beetle (Tribolium confusum); Sawtoothed grain beetle (Oryzaephilus surinamensis)

What to look for

  1. Snout first. Maryland says rice and granary weevils have a distinct elongated snout visible on the head. NC State calls it the mark of most weevils.
  2. Length. Maryland gives the rice weevil as 1/8 inch (3.2 mm) and the granary weevil as 1/8 to 1/4 inch (3.2 to 6.4 mm). Kentucky gives rice weevils as 1/8 to 1/4 inch and the flour, sawtoothed grain, drugstore and cigarette beetles as 1/8 inch (3.2 mm).
  3. Color and marks. Rice weevils are dull reddish brown with four faint reddish to yellowish marks on the wing covers; granary weevils are reddish brown to black and lack those pale spots.
  4. Teeth on the thorax. NC State says sawtoothed grain beetles are named for the row of large teeth on the sides of the thorax near the head, and that merchant grain beetles carry the same saw-like features.
  5. Which one flies. The rice weevil flies and is attracted to light, the granary weevil does neither. Kentucky adds that confused flour beetles fly toward light while red flour beetles crawl toward light but apparently do not fly.
  6. The larva. Maryland and NC State both describe weevil larvae as legless, creamy white to white with a darker head. NC State adds they are humpbacked.

Where and when

Kentucky extension says the first sign is usually small beetles crawling over countertops or moths flying across a room, and that the initial source is often a partly used box or bag forgotten at the back of a pantry. Maryland adds that unopened containers must be checked too, and lists nutmeats, dried fruits, flour, meal, pasta, breakfast cereals and spices, especially red pepper, paprika and chili powder.

Does it matter?

Kentucky extension says weevils develop inside whole kernels while flour and sawtoothed grain beetles cannot attack whole or undamaged grains and feed instead on flour, meal, dried fruit, dry dog food and similar processed products. NC State says granary weevil mouthparts may look threatening but they do not bite people. Both put the remedy in disposal of infested products, a thorough cleanup and sealed storage containers.

Related guides

  • Carpet beetle: Carpet beetles are small oval beetles, 1/16 to 1/8 inch long, that Kentucky extension describes as black or mottled with white, brown, yellow and orange.
  • Fungus gnat vs fruit fly: Where it came from answers it faster than how it looks.
  • Silverfish: A silverfish is a wingless, flat, teardrop-shaped insect covered in silvery scales, with long thread-like antennae and three tail-like appendages at the rear.

Sources