In a continuing fight over the use of its herbicide technologies, Monsanto Co. has called for a probe of industry rival E.I. du Pont de Nemours & Co. for what it described as “deceitful” attacks on Monsanto’s business practices, the St. Louis Business Journal reported.

Monsanto Chairman and CEO Hugh Grant sent a letter Monday to DuPont Chairman Charles Holliday Jr., demanding that he appoint a committee to investigate the alleged attacks, which Grant called “misleading to the public and a serious breach of business ethics far beyond honest competitor behavior.”

Monsanto has accused DuPont of writing forged letters to Congress, spreading misinformation, trying to improperly influence public officials and hiring “masked third parties, such as Weber Merritt.” Weber Merritt LLC, a Washington, D.C.-based public relations firm, recently promoted a conference held in St. Louis by the Organization for Competitive Markets, a Lincoln, Neb.-based group that criticizes Monsanto and is financed by DuPont.

Monsanto spokesman Lee Quarles characterized the alleged attacks as a multiyear smear campaign perpetrated by DuPont against Monsanto.

DuPont spokesman Anthony Farina said the company received Monsanto’s letter. He said DuPont wasn’t alone in its concerns about Monsanto’s business practices and pointed to an ongoing investigation by a group of state attorneys general.

In May, Monsanto sued DuPont to prevent what it called “unlawful use” of Monsanto’s herbicide-tolerant technologies in soybeans and corn. In that suit, Monsanto alleges that DuPont subsidiary Pioneer Hi-Bred International Inc. is “misusing” Monsanto’s Roundup Ready trait. DuPont countersued in June, arguing that combining its technologies with Monsanto’s was within its rights under its license agreement with Monsanto.

“We will not try these important issues through the media, and we look forward to having these issues decided in court – where Monsanto initiated this,” Farina said. “In addition, it appears the Obama Administration may also be concerned. Just last week the U.S. attorney general (Eric Holder) and the U.S. secretary of agriculture (Tom Vilsack) announced unprecedented joint hearings to study competition in agriculture, including seed traits.”