Sitophilus zeamais, maize grain weevil
Sitophilus oryzae, rice weevil
Sitophilus granarius, granary weevil

Nature of damage

• Infest stored grain or maize ears before harvest.
• The larvae develop into pupae inside the kernel.

Signs

• Removal of husks in the field will reveal weevils and the irregular punctures they make in kernels during feeding or egg laying (Sitophilus zeamais).
  - The rice weevil, smallest of the three species, rarely flies but is otherwise similar to the maize weevil, which is a strong flier.
  - The granary weevil also resembles the maize weevil, but cannot fly and lacks its four reddish spots on the wing covers.
• In kernels dislodged from the cob, one can readily observe thread-like galleries made by the legless, stout, whitish grubs as they feed inside the kernels.

Geographic distribution

• Worldwide distribution