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Volatility Not to Blame for 2017 Off-Target Dicamba Movement, Says BASF

Instead, Improper Use of The Technology is To Blame, Says BASF

This season’s off-target movement of dicamba used in dicamba-tolerant soybeans was due to a number of reasons, but volatility wasn’t one of them, say BASF officials.

Volatility results when a herbicide converts to a gas. When this happens, the herbicide in a gaseous form can leave the application site and damage plants where it lands.

“From a number of field investigations last summer, we identified multiple contributing factors, and we don’t believe volatility is one of those driving factors,” says Chad Asmus, BASF technical market manager. Asmus and other BASF officials held a conference call on November 17 with the agricultural media. 

BASF makes and markets Engenia, one of the new dicamba formulations in Monsanto’s dicamba-tolerant Roundup Ready Xtend System. The other two approved dicamba formulations are Monsanto’s Xtendimax with Vapor Grip Technology and Dupont’s FeXapan Plus Vapor Grip Technology.

Damage Tally

Recent data tallied by University of Missouri weed scientists indicate 2,708 dicamba-related injury cases are currently under investigation by various state agriculture departments. Approximately 3.6 million acres of soybeans were injured by off-target dicamba movement during 2017. USDA pegged total U.S. soybean plantings last June 30 at 89.5 million acres. 

“While most growers achieved great results stewarding DT crops this season, some non-DT farms experienced symptomology that may have come from the improper use of the new technology,” said Asmus in a news release. “BASF worked with growers to better understand what was occurring.” BASF officials say its field reps investigated 787 soybean symptomology claims during the 2017 season, most of which had no impact on yield. However, in a few isolated cases, BASF officials say yield may have been affected where the terminal growth was inhibited. Main causes include:

  • Incorrect nozzle and/or boom height 
  • Wind speed or direction 
  • Insufficient buffer 
  • Spray system contamination 
  • Use of unregistered product 

Still, the new formulations of dicamba can volatilize. Earlier this year, laboratory tests by University of Arkansas weed scientists found the three new formulations to be less volatile than older formulations like Banvel and Clarity.

“However, when you look at the new formulations in a field setting where volatility measurements are based on soybean injury, differences in volatility between older dicamba products such as Clarity and newer ones including Engenia and Xtendimax are not as evident,” said Tom Barber, a U of A weed scientist in a U of A news release.  “Although the new formulations are reduced in the amount of volatility that you can see, they’re not zero. We don’t know the level of volatility that’s required to injure soybeans. Soybeans are so sensitive, very, very low levels of volatility can cause injury.” 

Arkansas Dicamba Ban 

In other Arkansas developments, the Arkansas State Plant Board members earlier this month voted to ban dicamba use between April 16 and October 31.

This has prompted Monsanto to amend its complaint in Arkansas’ Pulaski County Circuit Court in response to the Arkansas ban. Monsanto also has released reports of suspected dicamba injury visits. At of October 26 this year, it has had:

  • 1,467 applicator inquires
  • 1,418 site visits
  • 1,222 applicators who supplied sufficient data for review and climatological evaluation.

Monsanto officials say in 91% of cases, applicators have self-reported errors from one or more label requirements checked that could have contributed to off-target movement.

Weed Control

There’s far less disagreement on the weed control performance of the new dicamba formulations. “Farmers are saying they have the cleanest fields in years,” says Scott Kay, BASF vice president for U.S. crop protection.

BASF released results of a recent survey of 400 U.S. soybean and cotton growers. BASF officials say the surveyed farmers rated weed control from Engenia herbicide an 8.6 out of 10 nationally (on a scale of 1 to 10 with 10 being best). BASF officials added that 85% of farmers surveyed planned to use Engenia in 2018 and 83% planned to recommend it. 

Still, the potential for off-target movement has prompted federal regulators to amend the dicamba labels for dicamba-tolerant soybeans

So have states, although some like Missouri have taken a less restrictive approach than Arkansas. Earlier this week, the Missouri Department of Agriculture issued its rules for 2018. It has mandated training for application of this now Restricted Use Pesticide (RUP). It has tightened the federal label for application time in Missouri from sunrise to sunset to 7:30 a.m. to 5:30 p.m.

The MDA also prohibits use of Engenia in dicamba-tolerant soybeans and dicamba-tolerant cotton after June 1, 2018, in 10 southeastern Missouri counties. The MDA also prohibits use of Engenia in dicamba-tolerant soybeans and dicamba-tolerant cotton after July 15.

2018 Plans

In preparation for next year, BASF says there will be an increased emphasis on training and education for dicamba applications.

BASF plans to expand its On-Target Academy workshops and also promote proper nozzle selection and broadcast spray hoods, says Asmus.

“We are committed to working collaboratively so everyone can receive the training they need for a successful 2018 season,” says Asmus. 

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