Granary Weevil

Category: LW
Minimum Life Cycle: 28 days.
Distribution: Temperate zones; northern distribution; attacks cereal grains.
Biology:
Eggs - Up to 200 per female laid within grains.
Larvae - Within grains; can survive at least 10 weeks at 5°C.
Adults - Flightless; easily overwinter in unheated buildings and bulk grain.

Granary Weevil (Sitophilus granaries). The granary, rice, and maize weevils feed on both unbroken and broken grain kernels. The granary weevil is unable to fly. It can be easily separated from the rice and maize weevil in the adult stage by the presence of elongated pits on the surface of the thorax, and by the absence of flight wings and colored markings on the wing covers. It is tolerant of low temperatures and cold climates and is seldom found in semitropical areas. This weevil can subsist in nature on acorns (Figure 1).

(Slide and top caption courtesy of ICI Americas, Inc.)

illustration of a granary weevil

Figure 1. Granary weevil.