What is "fall armyworm"

n. larva of a migratory American noctuid moth; destroys grasses and small grains [syn: Spodoptera frugiperda]

The fall armyworm (Spodoptera frugiperda) is part of the order of Lepidoptera and is the larval (see caterpillar) life stage of a fall armyworm moth. It is regarded as a pest and can wreak havoc with crops if left to multiply. Its name is derived from its feeding habits. They will eat everything in an area, and once the food supply is exhausted, the entire "army" will move to the next available food source.