RIO GRANDE VALLEY, Texas >> Alexandra, a 55-year-old immigrant living in the country illegally, was on her way to work at a watermelon farm in the border city of Edinburg, Texas, recently when her oldest son stopped her before she stepped out of her aging trailer.

“Please don’t go. You are going to get deported,” he told Alexandra, who asked that her last name not be used because she did not want to attract attention from federal immigration agents. Her son then showed her graphic videos of federal agents chasing and handcuffing migrants seemingly all over the Rio Grande Valley of Texas. “That could be you,” he said.

President Donald Trump’s conflicting orders to exempt, then target, then again exempt farmworkers from his aggressive immigration sweeps of worksites have caused havoc in agricultural industries across the country, where about 42% of farmworkers lack permanent legal status, according to the Agriculture Department.

But perhaps nowhere is fear among farmworkers more palpable than on the farms and ranches along the southwestern U.S.-Mexico border, where for centuries workers have considered the frontier as being more porous than prohibitive.

Administration officials have vowed to make good on a once-popular campaign promise from Trump to deport millions of workers lacking permanent legal status, in what he has said will be the largest mass deportation in U.S. history.

As workplace raids have eroded that popularity and sparked angry protests across the country, the border region has been eerily quiet.

The Trump administration has effectively shut down crossings by those on the Mexican side seeking asylum or just illegal work in plain sight in the fields. On the American side, where immigrants living in the country illegally still make up much of the workforce, many of those workers are afraid to show up.

“Right now, I have zero workers,” said Nick Billman, who owns Red River Farms, a farm-to-table operation in Donna, Texas. He wonders whether to plant if he has no one to maintain the fields and harvest them. “We need to figure out what we’re doing, you know?”

It is difficult to estimate how many workers have stopped going to work. But Elizabeth Rodriguez, an activist with the National Farm Worker Ministry, says she is seeing fewer and fewer workers at the farms she frequents as the watermelon season is about to end.

“The majority of workers here are longtime residents who for some reason or another don’t have legal status,” Rodriguez said. “And now, they are terrified to go to work. The fields are nearly empty.”

Workers lacking permanent legal status have long been the lifeline of farms along the border region. In the most recent survey published by the National Center for Farmworker Health, about 80% of surveyed workers in Hidalgo County said they were in the country illegally. And the county, the largest in the Valley, as the region is known, has more than 2,400 farms.

Legal farmworkers with H-2A visas, which allow mostly Mexican nationals to work and live while they labor on farms, make up only a small percentage of the workforce, according to the same study.

“Clearly these farmers need these workers,” Rodriguez said. “How are Americans going to get the food they eat?”