Optimizing Late-Planted Crops

When weather and other factors force growers to plant crops later than expected, many elements can contribute to a profitable growing season.
A cornfield in Illinois is still snow-covered in April.
A cornfield in Illinois is still snow-covered in April.
It’s the beginning of May, and temperatures in the Midwest are finally starting to rise. Lingering cold temperatures and excess moisture in the region have caused many growers to experience planting delays. Whenever growers are forced to wait for temperatures to rise, experts recommend they take the extra time to evaluate their seed treatment selection and fine-tune their weed and disease management strategies.

Don’t Skimp on Seed Treatments

Cold, wet soils are favorable for the development of seedling diseases, such as Pythium and Phytophthora. Therefore, careful variety selection combined with a robust seed treatment is essential when planting late to help protect against early-season diseases, preserve crop quality and increase yield potential.

In some cases, weather can delay planting for so long that growers may consider changing their corn hybrid or variety selection. Syngenta agronomists say growers should wait until the last week of May to consider changing corn hybrid selections. The University of Minnesota shared the following timing guidelines:

  • May 25 – 31: Plant hybrids that are 5 to 7 relative maturity units earlier than a full-season hybrid.
  • June 1 – 10: Plant hybrids that are 8 to 15 relative maturity units earlier than a full-season hybrid.
  • June 11 – 15: Plant hybrids that are 15 or more relative maturity units earlier than a full-season hybrid.

Use the #Plant18 weather delay to make sure your weed and disease management plan is strong

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For soybeans, growers who are looking at planting after June 15 should consider varieties that are 0.5 or 1.0 maturity group earlier.

To help protect soybean varieties’ genetic potential against cold weather conditions, consider a seed treatment. “As the environment changes, use a seed treatment that will provide broad-spectrum control for insects and diseases,” says Leon Hunter, agronomy service manager at Syngenta. “Poor seed treatment selection will put growers further behind from desired planting dates because of loss of stand due to various diseases and insects. The last thing you want do is replant. Protect your seed selection by investing in a broad spectrum seed treatment.”

For the best protection against soybean diseases and insects, Hunter recommends using CruiserMaxx® Vibrance® Beans seed treatment, a combination of separately registered products. It delivers broad-spectrum protection against damaging early-season diseases, including sudden death syndrome, brown stem rot and white mold. It also supports strong emergence and standability in a variety of soil temperatures.

Thoroughly Evaluate Residual Herbicides

Once favorable growing conditions occur, it’s only a matter of time before weeds emerge. “When planting late, it’s all about getting control of weeds early,” says Don Porter, technical product lead at Syngenta. “Early weed control is even more important when planting late because crops will have less time to grow and mature.”

Porter recommends that growers take this extra time to thoroughly evaluate their herbicide selections for application flexibility, residual control and crop safety.

  • Application Flexibility – While optimal application timing for preventing early-season weed competition is pre-emergence, selecting pre- and post-emergence herbicides can help alleviate the negative effects of weather-related application delays. “Make sure a pre-emergence herbicide is part of your plan,” says Porter. “Pre-emergence herbicides can be applied with a burndown application, making your fields more prepared for the season. Don’t miss the opportunity to start clean.”
  • Residual Control – Overlapping residuals are key to effectively controlling weeds. “Early-season weed control sets growers up for good post-emergence weed control,” Porter says. Not using a post-emergence herbicide can often negate the hard work done by the pre-emergence herbicide. By using overlapping residuals, growers can control weeds before they emerge and become competitive with the crop.

    For soybeans, Porter recommends applying BroadAxe® XC, Prefix® or Boundary® 6.5 EC herbicides at pre-emergence. Each contains two effective sites of action to fight weeds, such as waterhemp, Palmer amaranth and grasses. Follow an application of BroadAxe XC or Boundary with Flexstar® GT 3.5, a post-emergence herbicide. Flexstar GT 3.5 is specifically formulated to fight weeds that are difficult to control with glyphosate alone or those that are glyphosate-resistant.

    For corn, Porter recommends applying Acuron® herbicide. Acuron provides application flexibility from 28 days preplant up to 12-inch corn and provides long-lasting residual control when applied at the full-labeled rate*.
  • Crop Safety – Porter says it’s crucial for growers to use a corn herbicide that delivers excellent pre- and post-emergence crop safety. Not all products include a crop safener, but Acuron contains the proven safener benoxacor, which provides crop safety even in adverse weather conditions when used according to the label.

Plan for a Robust Disease Management Regimen

“Growers can use this time to review their crop management plans and make sure their seeds, herbicides and fungicides are able to overcome anything Mother Nature throws at them.”

Leon Hunter
Corn and soybeans planted later in the season could potentially be impacted by diseases. In corn, diseases like Northern corn leaf blight, gray leaf spot and rusts can be a problem. Soybeans may be more susceptible to foliar diseases like frogeye leaf spot. Additionally, less mature plants can be more vulnerable to infection from pathogens that have had time to build in population size. These factors make it important to scout fields and follow disease progression from surrounding geographies, so that growers can make timely fungicide applications to help crops reach maturity and protect the yield potential.

“With the amount of moisture we’ve seen in the Midwest, growers should scout fields throughout the season,” says Hunter. “As long as there is moisture in fields, there is potential for disease development.”

Hunter recommends growers manage diseases with a fungicide that has demonstrated performance year after year, like Trivapro® fungicide. Trivapro is the hardest-working, longest-lasting broad-spectrum fungicide available for corn and soybeans. Trials comparing one application of Trivapro at R1 in corn and R3 in soybeans have shown stronger residual control, higher yields and, ultimately, better ROI than competitive programs.

Growers shouldn’t waste time while waiting for fields to reach optimal planting conditions, Hunter notes. “Growers can use this time to review their crop management plans and make sure their seeds, herbicides and fungicides are able to overcome anything Mother Nature throws at them,” he says.

*If a significant rainfall does not occur within seven days after application, weed control may be decreased.