Several new herbicides have received a label for corn within the past two years, and most of them will be on the market in 2017.
Acuron (Syngenta)
Use: Preemergence: All corn types. Postemergence: Field, silage, or seed corn.
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 corn and 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. Do not apply postemergence to popcorn or sweet corn.
Acuron Flexi (Syngenta)
Use: Preemergence: All corn types. Postemergence: Field, silage, or seed corn.
Active ingredients (lbs/gallon): Bicyclopyrone 0.08 lb + mesotrione 0.32 lb + S-metolachlor 2.86 lbs
Use rate: 2.0 qt/acre on soils with less than 3 percent organic matter; 2.25 qt/acre on soils with 3 percent or higher organic matter. Maximum of 2.25 qt/year.
Target weeds: Same as Acuron, however, will be less effective without atrazine.
Timing: Apply from 28 days prior to planting up to planting postemergence from emerged to 30 inches tall or up to the 8-leaf stage on field, silage, and seed corn only.
Adjuvants: If applied postemergence to corn and 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 product can be used in areas having atrazine use restrictions. Do not apply postemergence to sweet corn or popcorn.
Armezon PRO (BASF)
Use: All corn
Active ingredients (lbs/gallon): Dimethenamid-P (Outlook) 5.25 lbs + topramezone (Armezon-14) 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 germinating pigweeds and annual grasses.
Timing: Apply preemergence or 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 synergized when applied with atrazine. In K-State tests, there has been some crop injury with MSO type adjuvants and atrazine, however, corn recovered.
DiFlexx Duo (Bayer CropScience)
Use: All corn and fallow
Active ingredients (lbs/gallon): Diglycolamine salt of dicamba 1.86 lbs ae + Laudis 0.27 lbs + Bayer CropScience cyprosulfaminde (CSA) safener for corn only. Same form of dicamba salt as in Clarity.
Target weeds: The combination of dicamba and Laudis will provide excellent control of most annual broadleaf weeds, including kochia, pigweeds, velvetleaf, morningglory, sunflower, and others.
Use rate and timing: 24 to 40 fl oz per acre may be applied preplant or preemergence to field, silage, seed and popcorn up through V7 stage. With drop nozzles, can be applied up to corn at the V10 stage or 36 inches tall.
Adjuvants: Adjuvants may be used – COC or MSO at 1% v/v. UAN at 2 to 4 qt/acre or AMS at 8.5 to 17 lb/100 gallons are recommended on the label. The addition of AMS or UAN will increase the risk of dicamba volatility, however.
Comments: Will help manage glyphosate-resistant broadleaf weeds. 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.
Enlist Duo (Dow AgroSciences)
Use: Enlist corn
Active ingredients (lbs /gallon): Colex-D technology: 1.7 lbs dimethylamine salt of 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, but will contribute to Palmer amaranth management.
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: No adjuvants listed in the label.
Comments: Enlist Duo received a full federal label in November 2014. Review the label as many application restrictions are listed. We are still waiting now for foreign export approvals (most importantly from China) of corn produced from Enlist hybrids. Enlist Duo cannot be aerially applied. This product will reduce potential off-target movement of 2,4-Dwhen 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).
Instigate (DuPont)
Use: All corn
Active ingredients: Rimsulfuron (Resolve) 4.17% + mesotrione (Callisto) 41.67%.
Target weeds: Will have residual and foliar activity on annual grasses and several broadleaf weeds.
Use rate: Rates re 5.25 to 7 oz product preemergence to field corn 14 days before planting up through 2-collar corn. If applying postemergence, use 5.25 to 5.4 oz/acre. Use the higher rates preemergence on fine-textured soils or soils having greater than 3% organic matter. Do not apply to coarse-textured soils with organic matter less than 1%.
Timing: Used PRE from 14 days before planting till emergence and POST from emergence through 2-collar corn.
Adjuvants: Add COC, MSO, or NIS to enhance postemergence activity on emerged weeds. In addition, a nitrogen-based adjuvant, AMS or UAN, should be used unless prohibited by a tankmix partner.
Comments: Almost always follow up with a postemergence herbicide program.
Kochiavore (Winfield Solutions)
Use: Field corn
Active ingredients (lbs/gallon): 1.67 lbs ae 2,4-D LV, 1.67 lb ai bromoxynil, and 0.67 lb ae fluroxypry.
Target weeds: Broadleaf weed control, including kochia.
Use rate and timing: Use 1 to 1.5 pints in corn preplant, a minimum of 7 days ahead of conventional-till planted corn, post-plant preemergence to no-till planted corn, or postemergence, to field corn at V3 to V5. Kochiavore will cause injury to corn as it contains an LV ester formulation of 2,4-D. Kochiavore can be applied up to 2.5 pints on fallow. Maximum use rate is 3 pints/acre for a growing season.
Adjuvants: The use of a high-quality adjuvant may be used to improve weed control (Statement in label). Research at K-State suggests that the use of adjuvants may also increase crop injury from Kochiavore, however, should be considered when Kochiavore is applied for weed control in fallow or noncropland areas.
Comments: Do not feed or graze corn for 47 days following application or harvest grain for 90 days of application. Do not harvest grain within 70 days of application or allow meat or dairy animals to consume fodder, forage, or graze for 45 days following application to sorghum. Do not allow livestock to grazed fallow that has been treated with Kochiavore.
Resicore (Dow AgroSciences)
Use: All field corn and yellow popcorn
Active ingredients (lbs/gallon): 2.8 lbs ai acetochlor, 0.3 lb ai mesotrione, and 0.19 lb ae clopyralid.
Target weeds: Resicore has excellent PRE activity on pigweeds and most broadleaf weeds, and good control of annual grasses except shattercane. When applied with atrazine most common broadleaf weeds will be controlled. Resicore applied postemergence may not provide adequate control of emerged annual grasses thus should be tank mixed with a product having good foliar activity on the grasses.
Use rate: As a preemergence to field, grain, silage, seed and yellow popcorn, use 2.25 to 3.0 qts/acre from 28 days before planting up to emergence. Rate structure is based on soil texture and organic matter. Apply Resicore from 1.5 to 3 qts/acre early postemergence to all types of field, corn, up to corn 11 inches tall. Do not apply POST to popcorn.
Adjuvants: Add NIS at 0.25% v/v or COC up to 1% v/v to enhance postemergence activity. Do not use MSO or adjuvants containing nitrogen if corn has emerged. The exception is 1.5 qts of Resicore may be applied postemergence with glyphosate (on glyphosate resistant corn) or glufosinate (on Liberty Link corn) and AMS at 8.5 lb/100 gallons + NIS at 0.25% v/v.
Comments: DO NOT APPLY POST to sweetcorn or popcorn. Applying with atrazine will enhance broadleaf weed control.
Curtis Thompson, Weed Management Specialist and Extension Agronomy State Leader
cthompso@ksu.edu
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