Several new herbicides have received a label for corn, and most of them will be on the market in 2016.
Acuron (Syngenta)
Use: Corn – grain or silage
Active ingredients (lbs/gallon): Atrazine 1.0 lb + bicyclopyrone 0.06 lb + mesotrione 0.24 lb + S-metolachlor 2.14 lbs
Use rate: 2.5 qt/acre on soils with less than 3 percent organic matter; 3 qt/acre on soils with 3 percent or higher organic matter. Maximum of 3 qt/year.
Target weeds: Key broadleaf weeds include Palmer amaranth, waterhemp, kochia, marestail, velvetleaf, common cocklebur, and others. Most annual grasses in Kansas except shattercane likely won’t be controlled. Will provide improved control of large-seeded broadleaf weeds when compared to Lumax EZ or Lexar EZ.
Timing: Apply from 28 days prior to planting up to emerged corn that is less than 12 inches tall.
Adjuvants: If applied postemergence to weeds, use NIS at 0.25% v/v. COC can be used up to 1% v/v, but this may increase the risk of crop injury. Do not use MSO, AMS, or UAN.
Comments: This has been described as “Lumax on steroids.” The active ingredients are the same as Lumax, with the addition of bicyclopyrone, a new HPPD-inhibitor chemical. Acuron cannot and should not be used on grain sorghum; it will cause significant injury to grain sorghum.
Armezon PRO (BASF)
Use: All corn
Active ingredients (lbs/gallon): Dimethenamid-P (Outlook) 5.25 lbs + topramezone (Armezon) 0.1 lb
Use rate: 14 to 24 fl oz/acre, depending on soil texture and organic matter level.
Target weeds: The spectrum of weeds controlled postemergence is identical to Armezon. However, the addition of dimethenamide-P will provide residual that controls pigweeds and annual grasses.
Timing: Apply postemergence to corn up to V8 or 30 inches tall. Use directed application without atrazine when corn is 12 to 30 inches tall.
Adjuvants: When applying postemergence, use MSO, COC, or HSOC at 0.5 to 1% v/v or NIS at 0.25 to 0.5% v/v. Add a nitrogen fertilizer, either UAN at 1.25 to 2.5 v/v or AMS at 8.5 to 17 lb/100 gal.
Comments: Armezon PRO can be tankmixed with other corn herbicides. It is synergistic with atrazine. In K-State tests, there has been some crop injury with oil type adjuvants and atrazine.
DiFlexx (Bayer CropScience)
Use: All corn and fallow
Active ingredients (lbs ae/gallon): Diglycolamine salt of dicamba 4 lbs + Bayer CropScience cyprosulfaminde (CSA) safener for corn only. Same form of dicamba salt as in Clarity.
Target weeds: Weed spectrum will be the same as other dicamba products. Tank mixing with other corn products will provide control of kochia, palmer amaranth, waterhemp, marestail, ragweeds, and others.
Use rate and timing: As a preemergence, 8 to 16 fl oz/acre, from 14 days prior to planting up to planting time. As a postemergence, 8 to 16 fl oz/acre at spike through 6-collar stage. Maximum amount used is 24 fl oz per season.
Adjuvants: Adjuvants may be used – NIS at 0.25% v/v, COC or MSO at 1% v/v, and UAN at 2 to 4 qt/acre or AMS at 8.5 to 17 lb/100 gallons.
Comments: DiFlexx has a different safener than Status, and does not contain diflufenzopyr, which is in Distinct and Status. The safener in DiFlexx has soil and foliar activity.
DiFlexx Duo (Bayer CropScience)
Not registered as of February 1, 2016 but registration expected prior to corn planting.
Use: Corn
Active ingredients: DiFlexx and tembrotrione (active ingredient in Laudis)
Target weeds: The combination of these two active ingredients will provide excellent control of most annual broadleaf weeds, including kochia, pigweeds, velvetleaf, morningglory, sunflower, and others.
Comments: Will help manage glyphosate-resistant broadleaf weeds.
Enlist Duo (Dow AgroSciences)
Use: Enlist corn
Active ingredients (lbs /gallon): 1.7 lbs glyphosate acid and 1.6 lbs 2.4-D acid as a choline salt.
Target weeds: Glyphosate component will control many weed species that are susceptible to glyphosate, and the 2,4-D component will help manage several glyphosate-resistant broadleaf weeds, including pigweeds, marestail, morningglory, velvetleaf, and others. This product will be very weak on glyphosate-resistant kochia.
Use rate and timing: Use 3.5 to 4.75 pts/acre to corn no larger than V8 or 30 inches tall. Make 1 to 2 postemergence applications with a minimum of 12 days between applications. Enlist Duo may be used preemergence or postemergence. However, the total application cannot exceed 14.25 pts of Enlist Duo/acre per season.
Adjuvants: Adjuvants may be used – NIS at 0.25% v/v, COC or MSO at 1% v/v, and UAN at 2 to 4 qt/acre or AMS at 8.5 to 17 lb/100 gallons.
Comments: Enlist Duo received a full federal label in November 2014. We are waiting now for foreign export approvals (most importantly from China) of corn produced from Enlist hybrids. Enlist Duo cannot be aerially applied. This product contains Colex-D technology, which is a choline salt of 2,4-D that will reduce potential off-target movement when used according to the label. The gene in Enlist corn confers resistance to the “Fop” grass herbicides – fluazifop (Fusilade) or quizalofop (Assure II). Grass herbicides that will control volunteer Enlist corn include clethodim (Select Max and generics) and sethoxydim (Poast and generics). NOTE: There has been a Dow AgroSciences update as of January 27, 2016 regarding a court case involving a recent EPS motion concerning the registration of Enlist Duo. The court denied EPA’s motion to vacate the Enlist Duo registration. As a result of the decision, the current U.S. registration for Enlist Duo remains fully intact for all labeled uses
Resicore (Dow AgroSciences)
Use: All corn
Active ingredients (lbs/gallon): 2.8 lbs ai acetochlor, 0.3 lb ai mesotrione, and 0.19 lb ae clopyralid.
Target weeds: When used PRE and applied with atrazine will have excellent activity on pigweeds and most broadleaf weeds, and good control of annual grasses except shattercane. When used POST with atrazine will provide control of most broadleaf weeds; however, will not provide adequate control of most annual grasses.
Use rate: 2.25 to 2.75 qts/acre on soils with less than 3% organic matter (OM) and 2.5 to 3 qts on soils with 3% OM or greater. Maximum use rate per season is 3.25 qt/acre.
Timing: Used PRE from 28 days before through post planting and POST (prior to 11 inches tall field corn only).
Adjuvants: N/A.
Comments: DO NOT APPLY POST to sweetcorn or popcorn. Applying with atrazine will enhance broadleaf weed control. Postemergence activity on emerged grass is not adequate. To get grass control when used POST, it should be tankmixed with an herbicide having grass activity.
Revulin Q (DuPont)
Use: All corn
Active ingredients: 14.4% nicsulfuron and 36.8% mesotrione
Target weeds: Has activity on grass and broadleaf weeds. Best control will be attained if tankmixed with glyphosate (which enhances grass control) and/or atrazine (synergizes mesotrione, enhancing broadleaf weed control).
Use rate: 3.4 4o 4.0 oz/acre; not to exceed 2.0 oz/acre/season for grass and broadleaf weed control.
Timing: Apply to corn up to 20 inches tall or 6 collars, or with drop nozzles up to 30 inches tall or 8-collar corn, whichever is more restrictive.
Adjuvants: Apply with COC 1 to 2% v/v or HSOC at 0.5% v/v. NIS can be used at 0.25% v/v, however less weed control may be observed. Use an N source, either UAN at 2 qt/acre or AMS at 2 lbs/acre.
Comments: Do not apply with methylated seed soil (MSO). Rotational restrictions – wheat 4 months; alfalfa, canola, cotton, sorghum, soybeans, and sunflower 10 months.
Curtis Thompson, Weed Management Specialist and Extension Agronomy State Leader
cthompso@ksu.edu
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