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What’s Up for 2016 Corn and Soybean Herbicides?

Each year, marketing representatives of agricultural chemical companies extoll the virtues of new herbicides. 

What they’re actually discussing are tweaks made in existing herbicide sites of action. The last truly new corn and soybeans herbicides were HPPD inhibitors that debuted around 20 years ago.

That said, there are some changes in existing corn and soybean chemistries that have recently been made, says Mike Owen, Iowa State University (ISU) Extension weed specialist. Owen highlighted some of them at this winter’s ISU Integrated Crop Management conference. The following changes also include the product’s site of action group number and the herbicide site of action.

Armezon Pro from BASF is a new herbicide for corn (field, sweet, seed, and popcorn). Armezon Pro is an EC formulation containing topramezone (Group 27, HPPD inhibitor) and dimethenamid-P (Group 15, very long-chain fatty acid inhibitor). It may be applied from corn emergence up to V8 stage or 30-inch-tall corn (12 inches tall for sweet corn). It provides burndown and residual control of some annual broadleaf and grass weeds. Use rate range is from 14 to 24 ounces per acre, depending on soil texture and organic matter. 

DiFlexx from Bayer CropScience was registered for field, white, seed, and popcorn last spring. It’s a dicamba (Group 4, synthetic auxin) formulation with safener cyprosulfamide. It’s registered for preplant burndown, preemergence, and post-emergence application in corn. It has no planting restrictions due to safener inclusion. Postemergence applications can be made to corn up to the V10 stage. Observe the DiFlexx label recommendations for adjuvants. Use 8 to 16 ounces per acre with a seasonal total maximum of 32 ounces per acre. 

Capreno from Bayer CropScience is a premix of tembotrione (Group 27, HPPD inhibitor) and thiencarbazone-methyl (Group 2, ALS inhibitor). It also contains the safener isoxadifen-ethyl and is now registered to be applied to V7 corn stage. Apply Capreno to field corn, silage, and white corn from emergence to 20 inches tall. Do not apply when corn is taller than 20 inches or has 7 or more leaf collars, whichever is more restrictive. MSO has been added as an adjuvant choice. 

All Bayer CropScience labels will include new pest-resistance management language. The language is generally more detailed and reflects the need to diversify weed management. Besides herbicide sites of action, seed-bank management is emphasized in addition to scouting, controlling weed escapes, and crop rotation.  

Revulin Q from DuPont received EPA registration approval early in the first quarter of 2015. It’s a premix of dry mesotrione (Group 27, HPPD inhibitor), nicosulfuron (Group 2, ALS inhibitor), and a safener. Revulin Q is labeled for postemergence grass and broadleaf weed control in numerous types of corn including field corn grown for grain, silage, or seed; yellow popcorn; and sweet corn. 

Cinch from DuPont (Group 15, very long-chain fatty acid inhibitor) can now be applied as part of a sequential soybean weed-control program. 
If Cinch is applied as a preplant surface, preplant incorporated, or a preemergence treatment, it can again be applied postemergence provided that the total rate during any one crop does not exceed 2.5 pints per acre. No more than 1.33 pints per acre of Cinch can be applied postemergence. Postemergence applications must be made at least 90 days before harvest. Cinch does not control emerged weeds. 

Anthem Maxx from FMC is a premix of fluthiacet-methyl (Group 14, PPO inhibitor) and pyroxasulfone (Group 15, very long-chain fatty acid inhibitor) and replaces Anthem. Anthem Maxx has 4.3 pounds of active ingredient per gallon, double the active ingredient in Anthem. Anthem Maxx application rates will be one half the rate for Anthem. 

Anthem Maxx is registered for preplant burndown, preemergence, preplant incorporated, and postemergence application in field corn, sweet corn, popcorn, and soybeans. Postemergence applications in corn should be made through the V4 stage; in soybeans, it should be made through the V3 stage. Weeds should be small and actively growing. Observe application restrictions listed on the Anthem Maxx label. 

Warrant Ultra from Monsanto is a premix of encapsulated acetochlor (Group 15, very long-chain fatty acid inhibitor) and fomesafen (Group 14, PPO inhibitor). This product can be applied preemergence and postemergence before soybeans reach growth stage R2, and it will control many annual grass and broadleaf weeds. 

Encapsulating acetochlor provides a slow release of the herbicide and increases its potential to remain effective for a longer period of time. Warrant Ultra can now be applied to soybeans postemergence for extended residual control of some annual grass and broadleaf weeds. 

Acuron from Syngenta controls annual grass and broadleaf weeds in field corn, seed corn, silage corn, sweet corn, and yellow popcorn. Acuron is a premix of S-metolachlor (Group 15, very long-chain fatty acid inhibitor), atrazine (Group 5, Photosystem II inhibitor), mesotrione (Group 27, HPPD inhibitor), and bicyclopyrone (Group 27, HPPD inhibitor). 

Acuron can be applied preemergence in all corn types listed. It may also be applied early postemergence in field, seed, and silage corn but not to emerged sweet corn or yellow popcorn because of potential severe crop injury. Acuron may also be applied in split application. Postemergence applications must be made before corn is 12 inches tall. 

Another premix called Acuron flexi may be available for 2016, but it had not yet received federal regulatory approval at press time. This premix contains the same active ingredients as Acuron, minus the atrazine. It’s for those areas where atrazine can’t be applied or where atrazine carryover concerns exist, says Ryan Lins, a Syngenta research and development scientist based in Minnesota. 

Owen notes most of Syngenta’s proprietary herbicides now have the Weed Science Society of America (WSSA) mode-of-action herbicide group numbers and revised resistance-management language included in the label. 

FLEXSTAR (Group 14) and FLEXSTAR GT (Groups 9 and 14) labels now include an adjuvant statement that requires adjuvant products to meet the standards of the Chemical Producers and Distributors Association certification program. 

Fierce XLT from Valent is a new premix registered for use in soybeans. Fierce XLT includes chlorimuron (Group 2, ALS inhibitor), flumioxazin (Group 14, PPO inhibitor) and pyroxasulfone (Group 15, very long-chain fatty acid inhibitor) and can be applied as an early preplant, preplant, or preemergence application. Preemergence applications of Fierce XLT must be made within three days after planting and prior to soybean emergence. 

Fierce XLT applications after soybeans have begun to crack or are emerged will result in severe injury. Do not apply Fierce XLT on soils with a composite pH of greater than 7.6. Do not perform any tillage operation after application, or residual weed control will be reduced.

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