- Color: Reddish-brown
- Size: Very small, only 1/10 inch.
- Larvae possess legs, are off-white with a brown head, and 1/8 inch long.
- Flattened body shape.
- Six saw-tooth projects on their pronotum (the area just behind their head).
- Distinguishing the sawtoothed grain beetle from the merchant grain beetle is difficult, but the merchant grain beetle generally has a more triangular head shape and has small knobs just behind the eyes.
Habits of Sawtoothed and Merchant Grain Beetles:
- Adults and larvae feed on common stored-food products which includes cereals, cornmeal, cornstarch, popcorn, rice, dried fruits, breakfast foods, flour, rolled oats, bran, macaroni, sugar, drugs, spices, herbs, candy, dried meats, chocolate, bread, nuts, crackers, raisins, dried pet food.
- Are capable of boring into thin unopened packaging material, including through paper, cardboard, plastic, and foil.
- Populations build up rapidly once inside stored foods.
- Adults and larvae feed externally, feeding on small, divided food particles rather than whole grains.
- The sawtoothed grain beetle cannot fly, but the merchant grain beetle is capable of flight.
- A single sawtoothed grain beetle female can lay 300 eggs and a merchant grain beetle female can lay 200 eggs in her lifetime.
- A complete life cycle can be completed in a little as 27-35 days.
Damage Caused by Sawtoothed and Merchant Grain Beetles:
- Infested food is often ruined through contamination more than destruction.
- The beetles are harmless to humans and pose no risk other than loss of stored food.Look for:
- All life stages (egg, larvae, pupa, and adult) in stored foods.
- Infestations in older products or products with thinner packaging.
How to Control and Kill Sawtoothed and Merchant Grain Beetles:
- Locating and destroying/disposing the infested materials is the best method of control.
- Store all food in durable containers with tight-fitting lids
- Try to use products in a short amount of time to prevent the build-up of infested material.
- Clean all food areas with a vacuum to prevent beetles from breeding in spilled food or crumbs.
- Suspected foods can be treated to prevent beetle establishment by either heating to 120 F for one hour or freezing for four days.