- the larva of the noctuid moth Pseudaletia unipuncta, which advances over a region in massive numbers, suggestive of an army, destroying crops of grain and vegetables.
- any moth larva that is similar to the noctuid Pseudaletia unipuncta in its habit of advancing over a region in massive numbers, suggestive of an army, destroying agricultural crops.
- the caterpillar of a widely distributed noctuid moth, Leucania unipuncta, which travels in vast hordes and is a serious pest of cereal crops in North America
- any of various similar caterpillars
