Weevils
Weevils are small beetles with distinctive elongated snouts that allow them to bore into whole grain kernels, seeds, and legumes to lay eggs. The rice weevil, granary weevil, and maize weevil are the most significant stored grain pests worldwide. Female weevils chew a hole in a grain kernel, deposit a single egg, and seal it with a gelatinous secretion. The larva develops entirely inside the kernel, emerging as an adult, which makes early detection difficult. They are a major economic pest of stored grain, rice, corn, and dried pasta.
Species in This Group (3)
Rice Weevil
Sitophilus oryzae
The Rice Weevil is one of the most destructive stored-grain pests worldwide.
Granary Weevil
Sitophilus granarius
The Granary Weevil is a flightless grain pest that has been associated with stored cereals for thousands of years.
Bean Weevil
Acanthoscelides obtectus
The Bean Weevil infests dried beans and other legumes both in the field and in storage.
Key Behaviors
Female weevils use their elongated snouts to bore into whole grain kernels for egg laying. Larvae develop and pupate entirely within the kernel, making internal infestation invisible until adults emerge. Rice weevils are strong fliers and can infest grain in fields before harvest. Granary weevils are flightless and are associated exclusively with stored grain. They are commonly introduced into homes via infested rice, whole grain products, and dried beans.
Risks & Concerns
Weevils cause significant loss and contamination of stored grain products. Because larvae develop inside kernels, infestations can be well established before adults are visible. In commercial grain storage, weevil damage reduces grade and value. In homes, they infest rice, pasta, cereals, and dried beans, requiring disposal of contaminated products. Heavy infestations produce a characteristic musty odor.
Quick Comparison
| Species | Size | Color | Key Trait |
|---|---|---|---|
| Rice Weevil | 2.5-3.5 mm | Reddish-brown to black with four light spots on the wing covers | Elongated snout (rostrum); four pale spots on the elytra; larvae develop inside whole grain kernels. |
| Granary Weevil | 3-5 mm | Uniform dark brown to black without pale spots | Similar to rice weevil but uniformly dark colored and unable to fly. |
| Bean Weevil | 2.5-3.5 mm | Olive-brown to gray with darker mottled markings | Infests dried beans and legumes; adults emerge from stored beans leaving round exit holes. |
Need Help With Weevils?
If you're seeing signs of weevils in or around your home, professional treatment is the fastest way to stop the problem. Lotus Pest Control offers free inspections to identify the issue and recommend the right solution.