Should we ever intentionally drive a species to extinction? Most people probably agree with deadly diseases like smallpox and malaria, but what about the New World screwworm? Its very existence in the wild causes horrific suffering. Humans sometimes struggle to accept the fact that nature is amoral, because evolution doesn't care. Now, though, we have technologies that make it far easier to intervene than it ever has been, and we are faced with the choice of whether or not to use them. This a test of moral character as much as it is of scientific achievement. Do we care more about leaving the natural world untouched, knowingly allowing animals to suffer when we could intervene? Or do we interfere? Are we gardeners, or park rangers? And who gets to decide?