For many years the two phases were believed to be different species and the gregarious form was mistakenly identified as S. paranensis.

Plagues originate in a desert and semi-desert zona permanente in NW Argentina, SE Bolivia and W Paraguay, when good rains allow successful breeding, followed by gregarisation.

Swarms of gregarious adults may then migrate into crop growing regions.

[2] Schistocerca cancellata is polyphagous, damaging a wide range of crops and forage plants.

It was estimated that in 1933, locusts destroyed 2 million tons of cereals and other annual crops.