They pick the crops. Staff the restaurants. Mend the roofs. Mow the lawns. They work late at hospitals and airports. If you live in New Jersey, they probably pump your gas.

What happens if they disappear?

Unnerved by the high-profile arrests of 600 undocumented immigrants across six states last week -- not including Pennsylvania and New Jersey -- some Philadelphia-area businesses and restaurants that employ foreign-born staff, in the United States legally or not, are expected to take part Thursday in a "Day Without Immigrants" protest.

Organizers are asking owners to shutter shops, and workers to stay away from their jobs, keep children home from school, and generally avoid purchases or online shopping to demonstrate what would happen if large-scale immigration-enforcement operations were to happen here.

"We wonder how teachers will feel when in some classrooms most of their students will be gone, or how people who frequent our bodegas or corner stores will feel when they are closed," Miguel Andrade, of the South Philadelphia immigrant support group Juntos, said in a statement.

Carmen Guererro, an organizer with Coalicion Fortaleza Latina, a Norristown advocacy group, said about 20 businesses -- in the Montgomery County borough, in Philadelphia, Allentown, and King of Prussia -- have pledged to join in and post signs on their doors to explain why they are closed.

Participating businesses include restaurants, Mexican specialty stores, beauty salons, a roofing company, and a caterer, she said.

Driven largely by Facebook postings and other social media, the proposed one-day work stoppage takes note of President Trump's promise to rid the country of undocumented immigrants.

"Mr. President," reads one tweet designed to look like a leaflet, "without us and our contributions, this country would be paralyzed."

The tweet goes on: "Lose a day's pay, but gain much more."

The campaign, said Juntos director Erika Almiron, is a "sort of soft launch" for a bigger, nationwide, pro-immigrant general strike being organized for May 1.

Thursday's action could have a visible impact in area restaurants, some of which depend on immigrant labor.

David Suro, owner of Tequilas, a high-end Mexican restaurant in Center City, said: "I've been talking with my colleagues from some of the most influential restaurants in the city. The majority are more than willing to support this act to send a message on the role that immigrants play in our communities."

What if some of his workers stay away that day?

"I'm perfectly fine with it," said Suro, who was born in Mexico. "I'm  120 percent fine. As an immigrant myself, I'm not planning to show up."