Alabama argillacea, was a mysterious pest, suddenly appearing some years & largely absent in others, due to its migratory nature. No life stage of the Cotton Leafworm can tolerate frost or freezing. Areas that experience low temperatures must be re-colonized from warmer areas every year. Populations every year migrated from South America, sometimes using cotton in Mexico as a stepping stone in their journey northward.
Alabama argillacea, has gone from as serious pest to a seldom collected moth in the US. Many areas that formerly grew cotton were planted to other more lucrative crops. Practices changed to eliminate cotton stubs post harvest to deny pests a source of food in areas where they could survive. Taken together, these practices drastically reduced the number of migrating moths that reached North America. The recent adoption of BT cotton further reduces the population.
Large populations of Alabama argillacea, were largely created by the planting of cotton, providing the species with large areas of a new source of food. Changes in practices have reduced populations in North America to levels that were likely present before cotton production was expanded.
The Mystery of Alabama argillacea. 1929. George N. Wolcott. The American Naturalist. Vol. 63, No. 684 pp. 82-87