In an unusual move that could have ripple effects for the rest of the legislative session, the state House killed a proposal favored by the Senate’s top lawmaker Thursday.

The bill would ban genetically engineered grass seed designed to resist pesticides and herbicides, a product that isn’t yet on the market but is believed to be in development. Senate President Pro Tem Donald E. Williams, Jr., D-Brooklyn, pushed for the ban in his chamber, which passed it Wednesday night.

But House Speaker J. Brendan Sharkey, a fellow Democrat, was skeptical about the concept. And House Minority Leader Lawrence F. Cafero Jr., R-Norwalk, blasted both the substance of the proposal and its origins. The proposed ban never went through a public hearing because Williams added it as an amendment to another bill.

Typically, bills don’t come up for debate on the House or Senate floor unless their passage is assured. The grass seed bill came up under different circumstances Thursday afternoon: Its defeat was essentially certain.

In all, 37 House members voted for the bill, while 103 voted against it. Republicans Gail Lavielle and Tony Hwang were the only GOP representatives who supported the measure. Sharkey was among the Democrats who voted no.

Killing the bill now eliminates it as a potential issue for the rest of the legislative session, which ends May 7. But it could also produce tensions between Sharkey and Williams, who control the agenda in each of their chambers.

Sharkey said after the vote that he had “never ever been consulted on this bill by anyone in the Senate.” His chief concern about the measure, he said, was the lack of a public hearing.

Holding the vote Thursday was a way to keep the bill from becoming a distraction, Sharkey said. He noted that lobbyists had already started lining up to discuss it. “I just didn’t want to see our members distracted,” he said.

Sharkey said he didn’t think the vote would cause any of his priorities to be stalled in the Senate.

In response to the House vote, Senate Democratic leaders said in an emailed statement that there was plenty of public comment on the topic.

“Some of those who opposed the ban complained about the process. They failed to acknowledge that the initiative was discussed at two public hearings and that dozens of experts and citizens weighed-in,” the statement said.

Williams said in the statement that he was proud of what the Senate had accomplished, which he described as “taking a stand against the chemical companies and special interests which are poised to dump tens of thousands of gallons of pesticides on lawns across Connecticut.”

Senate Majority Leader Martin M. Looney, meanwhile, expressed disappointment at the House. “Despite the fact that research has extensively documented the adverse impact of poisonous chemicals on human health and the environment, all too often government ignores the precautionary principle and takes action only after harm occurs,” he said.

Williams, who is not seeking re-election this fall, has embraced the push to restrict the use of genetically modified organisms, including a proposal adopted last year that would require the labeling of food containing genetically modified organisms if other states adopt similar measures.

Proponents of the ban on genetically modified grass seed say Scotts Miracle-Gro Co. is developing seed designed to resist herbicides, which could encourage greater use of herbicides. Williams said Wednesday night that the use of GMO products has led to an increase in the use of pesticides and herbicides, with implications for the health of people and the environmental.

But critics of the measure, including some who supported last year’s labeling bill, say the proposed ban is not backed by scientific evidence. And they say the state shouldn’t be banning something that isn’t yet on the market.

Cafero was animated in his criticism of the bill during the House debate Thursday.

“What message are we sending to business?” he asked, noting the state’s efforts to rebound from the recession and attract jobs in a climate that many consider unfavorable to business.

And Cafero said it was insulting that the ban would come to the floor without a public hearing.

“Not one expert weighed in on this, not one member of the public, not one farmer, not one scientist came in to weigh in on this because we did not give them an opportunity to do so,” he said.

Several lawmakers spoke in favor of the ban, even if they were critical of the process that got it to the floor.

Rep. Philip J. Miller, D-Essex, a supporter, said 47,000 people had contacted legislative offices in favor of the measure. And Rep. Mary Mushinsky, D-Wallingford, said the proposed ban could protect the state’s children and waterways.

“This is our chance now to draw a line,” she said.