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Iowa: 2018 Season Recap

December 9, 2018
This agronomic image shows a Two-pass application of Acuron® corn herbicide 69 days after the second pass.

Charles City, IA, 2018: Two-pass application of Acuron® corn herbicide 69 days after the second pass.

Reminiscent of the childhood classic, “Goldilocks and the Three Bears,” IA’s weather spanned the spectrum this season. Generally speaking, the northern part of the state was too wet, the south too dry and the central portion just right. The heat was also above average across much of the state. So what did that mean for harvest and what can growers do to prepare for the 2019 season?

In Northern IA – where heavy rainfall from April onward hindered planting, delayed herbicide applications and flooded fields – growers saw some yield loss and will face challenges next season due to the weather’s impact on weed control. The same applies for the southern portion of the state where drought negatively impacted rain-activated herbicide applications and continued stressing crops going into late-season grain fill and harvest.

In Central IA where conditions were favorable for much of the season, disease was a concern. The combination of adequate moisture and warm weather provided optimal conditions for both gray leaf spot (GLS) and Northern corn leaf blight (NCLB).

Japanese beetles were an additional concern in many areas of IA. Populations were higher than in previous seasons, resulting in clipped corn silks and the defoliation of soybean leaves.

This agronomic image shows Japanese beetles feeding on corn silks.

Maquoketa, IA, 2018: Japanese beetles feeding on corn silks.

Heading into 2019, we recommend the following:

  • Be candid with your crop protection retailer about what you saw in 2018, and what worked and did not work. Regardless of conditions or geography, retailers can help customize a program to fit your needs.
  • Identify driver weeds and use corn and soybean herbicides with multiple, effective sites of action (SOAs) to fight resistance and reduce the weed seed bank:
    • To combat tough weeds like cocklebur, giant ragweed, morningglory and waterhemp in corn, we recommend a 2-pass system of Acuron® or Acuron Flexi herbicide pre-emergence followed by the remaining rate post-emergence, or a pre-emergence application of Acuron or Acuron Flexi followed by Halex® GT herbicide plus either an atrazine or dicamba product post-emergence. Applying Halex GT post-emergence adds an additional SOA. Each of these corn herbicide premixes contains multiple effective SOAs for built-in resistance management and provides long-lasting residual control, especially when layered in a 2-pass system.
    • In soybeans, the use of premixes like Boundary® 6.5 EC, BroadAxe® XC or Prefix® as soil-applied herbicides is key to managing resistant weeds. In some areas, only glufosinate and dicamba are viable post-emergence options, but these products require a soil residual tank-mix partner in order to be effective. In such cases, Boundary 6.5 EC, BroadAxe XC and Prefix are an excellent fit. In PPO-susceptible populations, Flexstar® GT 3.5 herbicide can be paired with strong residual pre-emergence herbicides for effective management.
  • Scout early and often throughout the season, keeping an eye out for disease and Japanese beetles:
    • Disease will likely be an issue in 2019. Step 1 to combatting disease and preserving yield is planting tolerant corn hybrids and soybean varieties. Step 2 is applying a fungicide that delivers preventative and curative activity. For that we recommend Trivapro® fungicide, the hardest-working, longest-lasting fungicide in its class for disease control and plant health in corn and soybeans.

If Japanese beetle pressure is high, consider making an application of Warrior II with Zeon Technology® insecticide in corn and or Endigo® ZC in soybeans along with your fungicide application.

This agronomic image shows a grower scouting though his soybeans.

Charles City, IA, 2018: A grower scouts through his soybeans.

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All photos are either the property of Syngenta or are used with permission.