The Granary Weevil is among the most destructive of all stored grain insects. The larvae develop inside kernels of whole grain in storage.
They are dark brown-black in color. It is about 2.5 - 5 mm in length. They possess a long slender snout and cannot fly. In the larval stage the weevils are legless, humpbacked white to creamy white, with a small, tan head. Weevils in the pupa stage have snouts like the adults.
The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen. Emergence holes of the granary weevil are fairly large and tend to be more ragged than smooth and round. Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion. The life cycle is about 30 to 40 days during the summer, and 123 to 148 days during the winter, depending on temperature.
Most of their life is spent within the grain kernel. Both larvae and adults feed on grain.