FMC Corp., the Philadelphia pesticide-maker, has moved its Princeton-area research and development group to a 515-acre former DuPont Co. experimental farm near Newark, Del., where it plans to spend $50 million over the next three years on an expanded R&D headquarters.

The upgraded FMC labs and offices will also help house a larger staff of FMC’s former DuPont researchers, in a so-far unfinished facility that DuPont stopped building in a cost-cutting move before its 2017 merger with Dow Chemical Co.

“They left us with the shell of a beautiful building -- concrete walls and roof,” plus new adjoining greenhouses, FMC spokesperson Ken Gedaka said. “That’s a fantastic facility. We need that space.” The money will also pay for research equipment, engineering, infrastructure, and utilities.

Most important, FMC kept DuPont’s Stine Research Center workforce -- 360 science and engineering staff, 150 contract workers, and 50 facilities employees -- and its experimental farm, with fields for soybeans, corn and other grains, vegetables, and tree-fruit orchards where chemicals and other controls can be tested on apples, peaches, and other crops.

Leading up to the new center, FMC last year transferred 45 of the 90 staff at its Ewing Township, Mercer County, N.J., research facility to the Delaware site. An additional 15 New Jersey staff retired or quit. And 30 have stayed on in New Jersey in office roles -- including regulatory compliance and support -- as the research moves to Newark, Gedaka said. The company also plans 13 new research positions in Delaware over the next three years.

State taxpayers sweetened the deal. Delaware’s Council for Development Finance voted two grants from the Delaware Strategic Fund, including $1.5 million for capital expenses, plus $142,000 as a “performance grant,” with both sums contingent on FMC’s keeping and adding the promised jobs.

DuPont scientists had feared DuPont’s 2017 merger with Dow Chemical would force a shutdown at the Stine office, lab, and experimental farm complex, and that the company would move some staff to larger labs in the Midwest, and lay off others as DuPont did at its main Experimental Station near Wilmington. (A reorganized DuPont Co. has since spent more than $200 million updating the station, though some of its businesses are now up for sale.)

But the European Commission found that the Dow-DuPont merger, along with the contemporary Monsanto-Bayer and ChinaChem-Sygenta marriages, would reduce pesticide research and boost prices. The commission’s antitrust office directed DuPont to sell part of its business and the Delaware research site to a rival that could keep the industry competitive.

FMC agreed to take over the Stine site, plus the DuPont insecticides, which include Rynaxypyr (it kills moths and caterpillars that eat fruits and vegetables) and Cyazypyr (kills citrus flies). . In exchange, FMC swapped its food and drug additives unit to DuPont. Jubilant scientists cheered FMC chief executive Pierre Brondeau as their work’s preserver.

FMC’s research effort is headed by Kathleen Shelton, chief technology office and vice president, who joined FMC as part of the deal with DuPont.

After the merger, Dow and DuPont pesticide and genetically modified seed businesses were combined. At the end of May, they were spun off as Corteva, a new, publicly traded company, which locally includes a headquarters office near Wilmington and a research building adjoining FMC’s Stine site. DuPont also kept one building near the complex. On Wednesday Corteva said it would give $1 billion to its investors in a share repurchase program, in hopes of boosting its share price.

“FMC is making a significant new investment in Delaware, and in a campus that has long been a center of world-class biotechnology and agri-science research,” said Delaware Gov. John Carney in a statement. Newark, near the University of Delaware, is also home to research facilities for Siemens, Air Liquide, W.L. Gore, and other multinational companies.

Worldwide, FMC plans to spend “nearly $2 billion” in R&D over the next four years, said FMC president Mark Douglas in a statement. The company also built a biology and fermentation research lab in Denmark recently, and counts a total of 23 research stations around the world, to be headquartered at Stine.