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Board weighs allowing new weed controls

Meetings set on proposals for corn, soybean systems by Glen Chase | December 17, 2014 at 2:17 a.m.

The State Plant Board will hold two public hearings Thursday on proposals to allow row crop farmers the option of using two new weed control systems based on the 2,4-D and dicamba herbicides.

Director Darryl Little said Monday that the board has been discussing the systems, one of which won federal approval for use in six states Oct. 15. The Environmental Protection Agency is still evaluating whether to allow the use of Dow AgroSciences "Enlist Duo" 2,4-D-based system in 10 more states, including Arkansas. The other weed treatment, developed by the Monsanto Company, is still awaiting federal approval.

"I am satisfied that everyone is going to do everything they can to try and use these products and not have any problems," Little said. "But we really won't know until we get it out there in the real world."

A key issue with the 2,4-D and dicamba, which are widely used but strictly regulated in Arkansas, is accidental drift, Little said. Cotton is very sensitive to 2,4-D. The herbicide is currently used when fields are prepared for planting. Current rules forbid its use after April 15, the date by which cotton plants typically begin surfacing after planting.

Dicamba is used primarily for weed control in corn fields. However, regular soybeans are particularly sensitive to the herbicide. While dicamba is used on corn as well as a lawns in Arkansas, Little said it has not been applied in great volumes near soybean fields when plants are in vulnerable stages of their growth cycle.

Many farmers plant several different row crops as a way to deal with changing commodity prices. About 3.3 million acres of soy were harvested in Arkansas in 2014, compared to 325,000 acres of cotton and 555,000 of corn. Despite the growing problem with herbicide resistant weeds, the state is expected to set per acre yield records for all three crops.

On Oct. 15, the EPA approved the use of Dow AgroSciences Enlist Duo system, a mix of glyphosate, more commonly known as Roundup, and 2,4-D choline, for controlling weeds in fields planted with corn and soybeans genetically engineered to tolerate the 2,4-D. It's also being developed for cotton. Farmers in six Midwestern states -- Illinois, Indiana, Iowa, Ohio, South Dakota and Wisconsin -- can use Enlist Duo.

It's now being considered for use in 10 more states: Arkansas, Kansas, Louisiana, Minnesota, Mississippi, Missouri, Nebraska, Oklahoma, Tennessee and North Dakota.

Monsanto developed the second weed control program, called the "Roundup Ready Xtend Crop System," based on a mix of glyphosate and dicamba for use with genetically modified corn and soybean seeds resistant to dicamba.

Its Xtend system is still awaiting EPA approval. On Friday, the U.S. Department of Agriculture issued an environmental impact statement saying that the genetically modified cotton and soybean seeds developed for the Xtend system should be unregulated. It issued a similar finding for Enlist Duo seeds earlier this year.

The state Plant Board will hold public hearings beginning at 9 a.m. Thursday on proposals to change the state's pesticide classification regulations to allow row crop farmers to use the two reformulated herbicides to kill weeds that are increasingly resistant to glyphosate-based chemicals. The hearings will be held at the board's offices at 1 Natural Resources Drive in Little Rock.

One proposed rule would create an exemption for Enlist Duo on Enlist Weed Control soybeans, cotton and corn.

More specific rules would limit its application to days when the wind is blowing away from adjacent crops or desirable vegetation and wind speeds are below 10 mph, and the average diameter of spray droplets must be greater than 300 microns.

Similar regulations would be applied to Monsanto's "M1691" herbicide, described as a mix of diglycolamine salt of dicamba, Round-up Xtend with Vapor Grip Technology, a premix of glyphosate and diglycolamine salt of dicamba and XtendiMax with Vapor Grip, a diglycolamine salt of dicamba to be used on Roundup Ready Xtend cotton and soybeans.

With this herbicide, average sprayer droplets would have to be greater than 400 microns in diameter, and a buffer zone of at least 400 feet would be maintained between the application area and adjacent susceptible crops or other desirable vegetation.

Neither herbicide system could be applied using crop dusters.

"From my understanding, most farmers will have to make a decision whether they want to use one system or the other and that the two systems aren't compatible," Little said.

Damon Palmer, U.S. seeds marketing director for Dow AgroSciences, said the company plans to use what it is calling a "stewarded introduction" program to familiarize growers with the Enlist Duo system to make farmers more familiar with diversifying weed control as well as provide application training to prevent drift.

Palmer said farmers are seeing more herbicide-resistant weeds in their fields.

He said Arkansas growers have been dealing with the problem a little longer than other parts of the country. "We're starting to see those same trends and same challenges across the country." Currently, resistant weeds affect more than 70 million acres of farmland across the U.S., according to Dow AgroSciences spokesman Kenda Resler-Friend.

John Combest, a spokesman for Monsanto, said in an email that Monsanto is also planning a slow rollout of the Xtend system, with limited commercial introduction of the cotton trait in 2015 followed by the soybean trait in 2016.

Jeremy Ross, a soybean agronomist for the University of Arkansas Division of Agriculture, said the two systems need to be used judiciously to avoid weeds developing resistance if 2,4-D and dicamba-based herbicides are moved from use as a pre-planting weed killer to applications during the growing season.

"Do we need this? My answer is yes. Do we need it on every acre? Probably not," Ross said. "It just gives us another tool that we currently don't have to combat some of these problem weeds."

However, Ross said that sensitive crops are going to face a little more pressure from the new herbicide systems.

"Two,4-D is as sensitive on cotton as dicamba is on non-dicamba beans," Ross said. "It's still the million-dollar question: How are we going to keep these products in the fields? Because both of these products can volatilize and move off target."

Business on 12/17/2014

Print Headline: Board weighs allowing new weed controls


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