Concept:Storage pests damage grains only after harvest while the grains are kept in stores.Explanation:Weevils are common insects that bore into stored cereal kernels and feed on them.Their infestation starts in the store, making them the main storage pest of cereals in West Africa.Stem borers, birds, and army worms attack crops while they are still growing in the field.These field pests do not normally affect harvested grains in storage.Thus, the major storage pest of cereals is the weevil.Answer:B. weevil