Georgetown Law
Technology Review

A single wound on a cow was once an open invitation to devastation. The New World screwworm, a parasitic fly, laid its eggs in the exposed tissue of livestock, and within hours, newly hatched larvae would begin burrowing into living flesh. Unlike typical maggots that feed on dead tissue, screwworm larvae consumed healthy tissue, carving deeper into their host and causing intense suffering, infection, and often death. By the mid-twentieth century, this pest was ravaging cattle across the southern United States, inflicting severe economic losses and threatening the livestock industry.

What ultimately stopped the spread of the screwworm was not poison or widespread culling, but a radical new idea: sterilize the pest itself. In a joint effort between the United States and Panama, scientists began irradiating male screwworm pupae, rendering them sterile before releasing them back into the wild. When these males mated, no viable offspring followed, and the population steadily collapsed. This strategy became known as the sterile insect technique (SIT). This Technology Explainer examines the scientific foundations of SIT, its practical implementation, and the regulatory framework that governs its use.