What is the saw-toothed grain beetle?
What is the saw-toothed grain beetle?
The saw-toothed grain beetle is another common stored-product pest, a "relative" of the larger grain borer, but smaller and with slightly different habits.
What does it look like?
- Size: 3-4 mm, slightly larger than a rice weevil.
- Body: flattened, elongated, dark to reddish-brown.
- Most distinctive feature: saw-toothed ridges along each side of the thorax, like a saw—hence the name.
- Head: each side of the pronotum has six tooth-like projections.
- Moves relatively fast.
Difference between saw-toothed grain beetle and larger grain borer
| Feature | Saw-toothed grain beetle | Larger grain borer |
|---------|--------------------------|---------------------|
| Size | 3-4 mm | 8-11 mm |
| Back | Saw-toothed ridges | Smooth, no teeth |
| Color | Dark brown | Blackish-brown |
| Bites through packaging | No | Yes |
| Crawling speed | Faster | Slower |
Diet of saw-toothed grain beetle
They prefer already damaged grains and processed foods:
- Broken rice, broken wheat.
- Flour, rice flour.
- Crackers, pastry crumbs.
- Dried fruit, nut pieces.
- Noodle fragments.
They cannot bite through whole grains or packaging like the larger grain borer, so they rely on other pests to "open the way"—they often co-occur with rice weevils.
Sources of infestation
- Brought in with flour, broken rice, etc.
- Emerging from old stored grain.
- Hiding in kitchen crevices.
Control methods
Same as other stored-product pests:
- Store all dry goods in airtight containers.
- Freeze newly purchased grain.
- Use food-grade diatomaceous earth for environmental treatment.
- Keep the kitchen dry and clean.