Corn Herbicide Choice Critical to Managing Weeds
Conditions at the start of the 2019 season were not favorable for many growers. They were, however, advantageous for early-season weeds. Delayed fieldwork, late planting, excessive rainfall and cool conditions, combined with herbicide resistance, meant countless tough weeds emerged safely and then grew past the optimal herbicide application height of less than 4”. Many of those tough weeds remained uncontrolled and went to seed, adding to the weed seed bank for 2020 and the likelihood that fields have increased weed pressure next season.
The corn herbicide trial at our Slater, IA, Grow MoreTM Experience site highlighted herbicide performance in this season’s less-than-ideal conditions. Here’s what we saw:
- Corn planted June 3.
- Preemergence herbicide applications made on June 3 and post-emergence applications made on June 25.
- Driver weeds included: giant foxtail, morningglory, redroot pigweed, waterhemp and velvetleaf.
Acuron® corn herbicide applied one pass preemergence. 71 days after treatment (DAT).
Acuron applied preemergence, followed by Acuron Flexi plus atrazine and glyphosate. 49 days after second treatment.
Acuron applied preemergence, followed by Halex® GT corn herbicide plus atrazine. 49 days after second treatment.
Lumax® EZ corn herbicide applied preemergence. 71 DAT.
Resicore® applied preemergence. 71 DAT.
Corvus® plus atrazine applied preemergence. 71 DAT.
Verdict® applied preemergence. 71 DAT.
To start clean and stay clean in 2020 and manage increased weed pressure, our recommendation is a burndown application of Gramoxone® SL 2.0 herbicide followed by:
- A preemergence application of Acuron or Acuron Flexi at the full labeled rate.
- A 2-pass application of Acuron or Acuron Flexi with half the rate applied preemergence, followed by the remaining rate post-emergence, plus glyphosate for an additional site of action (SOA).
Both Acuron brands provide burndown and residual control of tough weeds, and effective weed control can lead to higher yield potential. Trials show Acuron delivers 5-15* more bushels than other corn herbicides. With the commodity market we’re in right now, every bushel counts. In addition to higher potential yields, clean fields mean cleaner grain and less chance of being docked at the elevator for weed seed.
Other good options following burndown include Lexar EZ, Lumax EZ and Halex GT (post-emergence only). These corn herbicides provide long-lasting, broad-spectrum control of grass and broadleaf weeds.
Interested to know how the soybean herbicides performed in Slater, IA? Check out the soybean herbicide version of this post.
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Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations.
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*When applied preemergence and at full label rates. Yield advantage range based on 2016 Syngenta and University trials comparing Acuron to Corvus®, Resicore®, SureStart® II and Verdict®. For more information on Acuron versus an individual product, ask your Syngenta representative.