Posted 7 May 2007. Crop Management.

Be a Good Neighbor When Using Phenoxy Herbicides

Texas A&M University. coals.tamu.edu

Lubbock, Texas (April 23, 2007)--There's an old saying ..."good fences make good neighbors." While good fences often separate productive crop land and different crops, they do little to stop herbicide drift.

"Phenoxy herbicides containing the active ingredient 2,4-D are commonly used to burn down unwanted vegetation before farmers plant row crops," said Teresa H. Burns, Texas Cooperative Extension viticulture advisor based at the Texas A&M University System Agricultural Research and Extension Center at Lubbock. "Using phenoxy herbicides in close proximity to neighboring vineyards can cause a real headache for grape growers." Grapevines are perennials that begin growth and put on new leaves early in the spring, several weeks before row crops are planted. They are also sensitive to herbicide damage throughout the growing season. "Many High Plains grape growers have suffered significant economic losses from herbicide drift during the past 10 years," Burns said. "Grape losses from herbicide drift can reach as high as $10,000 per acre because affected vines either die or take several years to recover and regain normal productivity. "Grape and wine production contributes close to $1 billion to the Texas economy. We currently have about 2,900 acres of grapes in Texas, and more than half that acreage is on the High Plains and in West Texas."

Burns encourages row crop producers to be a good neighbor when using phenoxy herbicides, especially if there are vineyards in the neighborhood. "Here are some tips on using phenoxy herbicides responsibly," she said.

• Do not spray phenoxy herbicides within 1 mile of a vineyard from mid-March until the end of October.

• Consider using alternative chemicals, but remember that glyphosate herbicide can also drift and cause significant damage to grapevines.

As a result, planting glyphosate-resistant cotton in close proximity to a vineyard should be avoided, according to Dr. Ed Hellman, Extension viticulturist based at Lubbock.

• Always read and follow herbicide label directions.

• Shut down or postpone herbicide applications if the wind speed is greater than 5 mph, or if the wind changes direction.

• Do not spray when there is a risk of temperature inversion, or when temperatures exceed 85 degrees F.

• Set up herbicide application equipment to deliver large spray droplets, which are less likely to drift.

• Use air induction or drift-retardant spray nozzles on spray equipment.

• Use a thickener, drift-retardant or elasticizer in the herbicide tank.

• Use a less-volatile amine formulation of phenoxy herbicide rather than an ester formulation.

But be aware than amine formulations can also drift.

"The person applying a herbicide is responsible for minimizing the potential for drift that may cause crop damage in adjoining fields," Burns said. "But if we practice some common-sense, good-neighbor methods when planning and making herbicide applications, we help minimize crop damage from herbicide drift. It just makes good sense, and good neighbors."