Friday, June 9, 2023

New MOA Is A Welcome Addition

Extension specialists offer guidance on Brake herbicide in peanut.

Brake herbicide received approval from the U.S. Environmental Protection Agency for use in peanut in 2023. Each state agriculture department must also approve the label.

Brake (fluridone) injury on peanut.

University of Georgia Extension weed specialist Eric Prostko, says, “I have been working with this herbicide for 10-plus years and am very glad that peanut growers will have another tool in their toolbox.”

In anticipation of receiving that final label from the Georgia Department of Agriculture, Prostko offers the following questions and answers that might be helpful when thinking about adding Brake to your herbicide program.

Q:Who is the manufacturer of Brake herbicide?

A:Brake was developed by SePRO Ag (

Q:What is the active ingredient in Brake?

A:The active ingredient in Brake is fluridone, which is also sold in the aquatic weed control market under the trade name of Sonar. Fluridone was first registered for aquatic use in 1986.

Q:What is the mode of action of Brake?

A:Brake is a Weed Science Society Association/Herbicide Resistance Action Committee Group 12 herbicide. Group 12 herbicides block carotenoid biosynthesis in susceptible plants by inhibiting the phytoene desaturase enzyme. This ultimately leads to the destruction of chlorophyll and membrane lipids. 

Brake has the same MOA as Solicam/Zorial (norflurazon), which has been labeled in peanut since 1993 but has not been used that much.  

Q:How long has UGA been testing Brake for use in peanut?

A:Initial research on the use of fluridone in peanuts began in 2013.

Q:What rate of Brake should be applied in peanut?

A:Brake 1.2LC can be applied preplant (14 days) or preemergence at 12 ounces per acre (0.113 lbs active ingredient per acre) but no later than 36 hours after planting. Additional studies will have the goal of increasing this timeline after planting but before cracking/emergence. Brake needs at least one-half inch of rainfall or irrigation to be properly activated. Peanut seed must be planted at least 1.5 inches deep.

Q:Is Brake a stand-alone product? 

A:No. Brake should always be applied in combination with a grass herbicide (i.e. Dual Magnum, Outlook, Prowl, Sonalan or Warrant) and Strongarm (when rotations permit). It can also be tank-mixed with Valor.

Q:Which peanut cultivars has Brake been tested on?

A:Brake has been tested on the following peanut cultivars in Georgia: GA-06G; GA-16HO; GA-18RU; GA-20VHO; GA-12Y; AUNPL-17; TifNV High O/L; and FloRun 331. In some tests, GA-16HO has exhibited more leaf injury (bleaching) but yields were not reduced. Injury from Brake is more likely to occur when excessive rates are used and when environmental conditions are unfavorable, such as cold and wet weather.

Q:What are the crop rotation restrictions for Brake?

A:Current crop rotation restrictions for Brake are as follows: cotton = 0 months; soybean = 2 months; wheat/barley/rye = 8 months (5 months if grown as cover and not harvested); corn/sorghum = 10 months; and tobacco/sunflower = 18 months.

Q:Why should a grower consider using Brake in a peanut weed control program?

A:Brake is very effective on Palmer amaranth and adds an additional herbicide MOA to the peanut weed control toolbox, which is extremely beneficial for resistance management.

Q:Are there any additional requirements?

A:A copy of the Supplemental Label must be in the possession of the user at the time of application. Ensure that Break is approved in your state before using.

These pictures show a comparison from the program of UGA weed specialist Eric Prostko of a Valor-based peanut weed control program and a Brake-based peanut weed control program in Ty Ty, Georgia, in 2022.

Key Points On Brake Herbicide

North Carolina State University Extension peanut agronomist David Jordan says Brake herbicide controls many problematic weeds in peanuts, including Palmer amaranth, common ragweed and annual grasses. Here are some of the key points about its use in peanuts:

• Brake requires significant and timely water for activation. There will be virtually no weed control if there is no rain or irrigation.

• The use rate is likely 12 ounces per acre on most of our peanut soils. Based on research from years ago, I do not recall seeing significant damage to peanuts.

• Brake needs to be applied within 36 hours after planting. Do not apply Brake to emerged peanuts.

• Brake needs to be co-applied with another herbicide – Group 15s or Valor are possible options.

• My recommendation as tank-mix partner is a Group 15 (Dual, etc.) as a preemergence application. Valor plus Dual Magnum is a common treatment. Dual Magnum brings grass control and suppression of other weeds to the table along with what Valor controls. Neither of these herbicides are standalone. If you mix Brake and Valor and rain does not occur, there will be a gap in the grass control. A mixture of Dual Magnum, Brake and Valor is expensive and still needs water for activation for broad spectrum control.

• Having Brake as an option brings us a new mode of action (Group 12). That is very important. Until there is more widespread PPO resistance, utility of Brake may be limited. However, in Virginia, ALS-resistant and PPO-resistant common ragweed is an issue. Brake has the potential to make important contributions in that setting. However, see the next point if you grow wheat.

• If you are growing wheat for grain production, do not use Brake in peanuts. There is an 8-month restriction on planting wheat after Brake. There are conversations about how digging peanuts may negate this issue, but I would not rely on that to avoid injury to wheat.

• There is an 18-month rotation restriction for tobacco. There is not a restriction for corn, grain sorghum, cotton, sweetpotato or soybeans planted the following season. Use caution with other crops because of a lack of available data. Always follow label directions.

• In 2023, research plots will look at Brake programs compared with traditional programs. PG

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