For years , the American agricultural giant Cargill has been on relatively good terms with environmental advocates, praised for agreeing to a landmark moratorium on buying soybeans grown on deforested land in the Amazon rain forest.

In recent weeks, though, that relationship has soured over the company’s refusal to agree to a similar moratorium in another environmentally sensitive region of Brazil and, more broadly, over its failure to meet its anti-deforestation targets. This month, the environmental advocacy group Mighty Earth released a report titled “Cargill: The Worst Company in the World.”

The fierce reaction shows how corporations that fall short of ambitious environmental commitments can be received. And it demonstrates the speed with which a company can go from environmental leader to scourge in the eyes of some advocates.

“What was disappointing was that Cargill got lauded and then didn’t follow through,” said Nathalie Walker, a director at the National Wildlife Federation. “I don’t think anyone is taking a personal view or an emotional view about a company. It’s judging them by their actions.”