When Eric Herm heard in 2005 that genetically modified cottonseeds were the latest innovation on the market, he thought he should plant the crop on his family farm near Lubbock, Tex.

“I was like, ‘What’s so bad about this,’ ” he said of the seeds, which are a cheaper way to help crops resist weed and insect damage. “We’re saving money and labor.”

After learning that the “seeds are injected with the genes of herbicides and pesticides,” Mr. Herm became critical of the product. “I didn’t want to be consuming that,” he said. “And neither would you.”

Now, Mr. Herm is advocating a requirement to include warning labels on consumer products with genetically modified organisms, or G.M.O.’s. He is among a small group of farmers and environmental advocates pushing for the labeling of G.M.O. products in Texas. But the push is getting little support from the Republican-dominated state leadership or from major agribusinesses.