Competing against millions of acres of cotton, winegrowers fear federal approval of new herbicides to be used on genetically modified cotton seeds will wipe out the wine industry in the Texas High Plains.

As Paul Bonarrigo watched his grapevines dwindle, he was confident that heavy-duty herbicides, probably sprayed on crops by a nearby farmer, were drifting into his vineyards. For the past two years, his 44 acres in Hale County — once sprawling vineyards providing fruit for Bonarrigo's Messina Hof Winery — have not produced any grapes as they wither from chemical damage.

Other Texas winegrowers have seen similar damage, and they blame it on dicamba and 2,4-D, two high-volatility herbicides commonly used on cereal crops, pastures and lawns. Now, the state's vintners are alarmed that use of the chemicals may soon expand to include 3.7 million acres of cotton fields in the High Plains, where cotton is being invaded by weeds immune to the Roundup pesticide long used. 

The wine industry contributed close to $2 billion to the Texas economy in 2013, according to a report by the Texas Wine and Grape Growers Association. Bonarrigo said he thinks the industry is now in jeopardy.

The U.S. Environmental Protection Agency recently approved Monsanto's new formulation, called XtendiMax with VaporGrip Technology, which contains dicamba. The agency has also proposed to register Enlist Duo, a Dow AgroSciences formulation that contains 2,4-D. 

Both formulations will be used on cotton crops planted with seeds genetically engineered to resist the spray. Enlist Duo is already used on engineered corn and soybean crops in 15 states, and the EPA is proposing to approve it in 19 additional states — including Texas — and extend its use on engineered cotton seeds.  

"The approval of these formulations will wind up affecting every vineyard up there," Bonarrigo said. 

The EPA is expected to issue a final decision on Enlist Duo's proposal by early 2017.