But why bomb cotton fields with moths? Pink bollworms are a notorious cotton pest. Once they start eating their way through the seeds and fibers, they reduce the quality of the cotton dramatically. So the USDA's Animal and Plant Health Inspection Service came up with a plan. If they raised pink bollworms in a lab, dyed them red to make them identifiable, and then irradiated them to make them sterile they'd have a population that could safely be released into cotton fields. The idea is that if the wild pink bollworms mate with the sterile pink bollworm moths, instead of each other, the sterile moths won't be able to reproduce, effectively stopping an infestation in its tracks.