(Adds Monsanto letter to Arkansas governor, filing to state plant board, context)
By Tom Polansek
CHICAGO, Sept 7 (Reuters) - Monsanto Co pushed Arkansas authorities on Thursday to reject a proposed April 15 cut-off date next year for sprayings of the agricultural herbicide dicamba, which has been linked to crop damage across the U.S. farm belt.
The company further said that Arkansas' plant board should allow farmers in the state to use Monsanto's dicamba weed killer, called XtendiMax with VaporGrip, on crops engineered to withstand it starting next year.
Monsanto, BASF and DuPont sell dicamba herbicides under different brand names to be sprayed on U.S. soybeans engineered by Monsanto to tolerate the chemical. The chemical can also be sprayed on dicamba-resistant cotton.
In July, Arkansas temporarily banned the use and sale of dicamba herbicides after farmers complained the chemical was drifting away from where it was sprayed into neighboring fields and damaging crops that were not resistant to the chemical.
Arkansas previously had blocked Monsanto's XtendiMax herbicide because the company did not provide testing data that state officials wanted.
In a letter to Arkansas Governor Asa Hutchinson on Thursday, Monsanto Chief Technology Officer Robb Fraley said a "failed regulatory process" led to Arkansas being the only U.S. soybean-growing state that did not permit the use of XtendiMax on growing crops in 2017.
The recommendation for Arkansas to ban dicamba sprayings after April 15 next year, made last month by a state task force, "is not based on scientific data, much less on any scientific consensus," about crop damage linked to the chemical, Monsanto said in a filing with the state's plant board.
The company also suggested that crop damage that has been attributed to dicamba may not result in significant soybean yield losses at harvest.
The U.S. Environmental Protection Agency is separately considering banning sprayings of dicamba herbicides after a set deadline next year, state officials advising the agency told Reuters.
A cut-off date would aim to protect plants vulnerable to the chemical. In Arkansas, the proposed April 15 deadline would also prevent most farmers from spraying dicamba weed killers on growing soybeans, a major selling point for the products. (Reporting by Tom Polansek in Chicago; Editing by Sandra Maler and Grant McCool)