After collecting more data, the E.P.A. in 2016 again approved registrations for the use of sulfoxaflor, but not on blooming crops that attracted bees and other pollinators. On July 12 of this year, however, the agency announced it had removed the restrictions and approved other uses for the insecticide, calling it “an effective tool to control challenging pests with fewer environmental impacts.”

The decision “shows the agency’s commitment to making decisions that are based on sound science,” Alexandra Dapolito Dunn, the assistant administrator for the E.P.A.’s office of chemical safety and pollution prevention, said in the announcement.

The Trump administration has been rolling back environmental regulations it sees as burdensome to the fossil fuel industry and other big businesses. In some cases, agencies have skipped key steps in the process, like notifying the public and asking for comment.

Mr. Loarie, the lawyer for the beekeepers, said the suit aimed to set aside the E.P.A.’s decision on sulfoxaflor because it was “contrary to federal law and unsupported by substantial evidence.”

He said in a telephone interview on Wednesday that the agency’s July decision to approve use of the insecticide was “out of the blue” and that it had not solicited public comments or feedback from the beekeeping industry, as it had done in 2013, in light of the industry’s history of legal objections.

“To cut them out of the process is definitely something we have not seen before,” Mr. Loarie said.

An E.P.A. spokesman said that the agency does not comment on pending litigatio n. He said the agency had sought public comments in previous stages of registering the pesticide, receiving “considerable feedback on sulfoxaflor from stakeholders.”

Corteva said in a statement on Wednesday that it was “pleased that the U.S. E.P.A. has restored and expanded” the use of one of its insecticides that has sulfoxaflor as its active ingredient.