Content ID


Sponsored: Determine Corn Growth Stages to Plan In-Season Applications

Postemergence applications require careful planning and timing. Watch the video below of Mycogen Seeds commercial agronomist Adam Owens on accurately determining corn growth stages for in-season herbicide, fungicide and nitrogen applications.

As you get in the field, here are some other tips to consider.

Fertilizer Applications

  • Determine if you need additional nitrogen: Nitrogen deficiency usually appears as a V-shaped yellowing of the lower or older leaves of the plant. Take in-season soil and leaf tissue samples to determine nitrogen concentration.
  • Plan your application style: There are two common ways to apply nitrogen. Inject it directly into the soil by deep-banding anhydrous ammonia. For UAN, coulter-inject is preferred due to its ability to minimize volatilization and foliar damage. Broadcast or top-dress applications of urea or ammonium sulfate are an alternative. Be sure to follow label directions to avoid foliar damage in later corn growth situations.
  • Use a stabilizer: Adding a nitrogen stabilizer can help keep nitrogen in its optimum form and remain available in the root zone between the critical V8 and VT stages.

Herbicide Applications

  • Scout fields after herbicide applications. After postemergence applications, scouting allows you to give priority to identified at-risk fields where herbicide-resistant weed concerns exist.
  • Follow product label directions: With a large variety of herbicides on the market, it is as important to follow product label directions to avoid herbicide injury. Know your crop stage to avoid causing stress from pre- or postemergence applications. Misapplication of herbicides can result in issues with germination, ear development and pollen shed.

Fungicide Applications

  • Understand hybrid tolerance: Hybrids more susceptible to fungal diseases will have a much better response to the use of a fungicide. Look back at your hybrid selections and determine which fields should be monitored during the growing season. Corn-on-corn situations are more challenged with foliar diseases – prioritize those field as you scout.
  • Scout fields prior to tasseling: Common fungal diseases include gray leaf spot, northern corn leaf blight and eyespot. If you find any of these diseases, calculate the number of disease incidence. If at least 50 percent of susceptible hybrids are showing symptoms, consider a fungicide application. Follow label directions and apply fungicide at the correct rate for your corn’s growth stage. Silage growers should also adhere to any restrictions on spray quantities and your projected harvest dates.

To learn more about growing season crop management, visit or talk to your local Mycogen Seeds agronomist.

Read more about

Crop Talk