Every day, planes drop millions of sterilized flies over the Panama-Colombia border. It sounds like a sci-fi horror plot, but it’s actually a decades-long strategy to stop screwworms—flesh-eating pests that once ravaged livestock across North America.

The plan? Raise screwworm flies, sterilize them with radiation, and release them into the wild. Since female screwworms only mate once, pairing with a sterile male means no offspring, gradually crashing the population. This technique eradicated screwworms from the U.S. by 1966, and today, a barrier in Panama keeps them from returning.

But now, scientists are exploring a game-changing alternative: gene drives. Using CRISPR, they aim to create a self-spreading genetic modification that makes female screwworms sterile, potentially wiping them out for good.

Could this finally end the battle against one of nature’s nastiest pests? SciShow explains it all—watch here: