After a 70 percent drop in Florida citrus production, EPA has approved two antibiotics to combat citrus greening—but it’s unclear if they help.

When Paul Meador, fourth-generation citrus farmer and owner of logistics company Everglades Harvesting, first noticed a pernicious disease impacting his southwest Florida citrus groves, he had no idea what it was. “It affected our tangerines first,” he says. “I called it sudden death.”

When it didn’t kill trees outright, the disease caused fruit to drop from the branches before it ripened. Soon, the illness had spread to the grapefruits, and then the juice oranges. Meador had no idea how to stop it. “There wasn’t anything to contain a disease you don’t know anything about,” he says.

Meader first noticed the symptoms in 2001, but it wasn’t until 2005 that he confirmed the illness was citrus greening, or Huanglongbing, a disease spread by a tiny insect known as the Asian citrus psyllid. Over time, infected trees lose productivity and eventually die. By the time Meador realized he needed to coordinate with his neighbors to target the insects responsible for spreading the bacteria, it was too late: The illness had besieged huge swaths of the state.

In Florida, citrus greening has led to a 70 percent drop in citrus production since it arrived 15 years ago. The rapid onset of the disease has left growers with few effective management strategies. Since 2016, the Environmental Protection Agency has allowed citrus farmers to spray medically important antibiotics on their groves in hopes of reversing the devastating trajectory.

But this last-ditch solution has its consequences: It’s expensive, and scientists aren’t sure it works very well, while public health advocates worry it’s hastening the spread of antibiotic resistance.