Corn and Soybean Management Down the Home Stretch

By Jerry Hartsock | Cutting Edge Consulting and Research Services

In-Season Corn Management


You’re down the home stretch as the VT/R-1 growth stage marks the transition from vegetative to reproductive growth stages. At this stage, no more kernels will develop. Potential for the ear has been set. Root growth slows. Huge demands are now on the plant for nutrients and water. At this time, pollen grains fall on receptive silks to pollinate the kernels to develop the grain. Black layer will occur approximately 55 days later.

Proper management and scouting are crucial to achieve maximum yield potential. Checking for successful pollination, silk clipping insects, nutrient deficiency symptoms and foliar disease is paramount while there is still time to control or correct any issues. Scout fields for activity by European corn borers, Western bean cutworms and corn rootworm beetles to take control measures. Ignoring issues can lead to significantly less yield and standability issues late in the season.

One corrective measure that may be required is applying a corn fungicide. There are many benefits to this management practice and it’s not just about disease control. In addition to fungicides, micro nutrients, insecticides and foliar nitrogen products can be beneficial if testing (tissue and soil nitrate) and scouting indicate there’s a problem or deficiency.

Why Use Corn Fungicides

  • Yield, yield, yield
  • Reduced stress caused by heat, drought, hail, wind, etc.
  • Much more efficient feeding at a complicated time of ear development and early grain fill
  • Stops or delays ethylene gas, which is a plant’s way of dealing with stress
  • Longer grain fill period
  • Disease control/suppression for 14 to 21 days
  • Greatly improved standability from less cannibalism of stalk and disease control
  • Cooler temperatures in the canopy
  • Significantly less wind damage if applied 48 hours prior to event
  • Target continuous corn fields, racehorse hybrids and high-yield environments for best results

Best Management Practices to Maximize Yield

  1. 1. Arrange application and products months in advance
  2. 2. Three GPA minimum gallonage
  3. 3. Full tassel and one- to four-inch silks equal prime strike zone (long before brown silks)
  4. 4. Target harvest at 24 to 25 percent moisture and above for 20 to 25 more BPA than letting grain field dry to the mid/upper teens
  5. 5. Corn plants need 50 to 70 percent of their nitrogen pre-tassel and for the next 45 days
  6. 6. Think and act like a 300+ BPA corn producer

Be on the lookout for late season stalk rot, which can occur from several factors, including:

  • Poor drainage
  • Low fertility in plant (potash, nitrogen)
  • Cannibalism of lower stalk due to nutrient deficiency
  • High populations
  • Significant number of cloudy days
  • Planted too shallowly
  • Compaction/poor root penetration
  • No fungicide use
  • Foliar diseases
  • Susceptible hybrid
  • Late harvest
  • Anthracnose, diplopia and gibberella stalk rots are the most common pathogens
Scouting AgVenture soybeans


The R-3 growth stage (3/16-inch pod in the top few nodes) marks the halfway point in soybeans. The majority of phosphorus and potassium still need to enter the plant. Peak demand for nitrogen is going on and will continue until almost maturity.

Scouting for defoliating insects such as Japanese beetles, bean leaf beetles, grasshoppers and various larvae, such as army worms, green clover worms and caterpillars needs to be intensified. Other insects such as soybean aphids and spider mites need full attention, as well.

Foliar diseases such as downey mildew, powdery mildew, frogeye leaf spot and cercospera can be an issue especially in wetter times and with humidity. Look out for vascular disease such as phytophthora, sudden death syndrome and brown stem rot. Scout for stem canker in the Southern Corn Belt.

Best Management Practices to Maximize Yields

  1. 1. Apply preventative fungicides at V-3
  2. 2. Apply insecticides to control the gamut of insects that might be present
  3. 3. Apply nutrients—sulfur, zinc, manganese, boron—as needed. Combinations of practices one, two and three (above) typically bring six to eight more bushels per acre with good stands, good fertility and good weed control
  4. 4. Avoid late season herbicide applications after significant flowering
  5. 5. Harvest at 13 percent and above moisture
Scouting AgVenture corn in-season.

Scout. Scout. Scout.

Scouting your fields is the most important practice you can perform pre-harvest. Darren Bakken, AgVenture seed and technology
manager, believes you shouldn’t wait until you’re in the cab of your combine to look for problems. “Issues are much easier to diagnose during the growing season and you can make a plan to harvest those problem fields early to minimize yield loss,” he said.

If you see an insect challenge while scouting, immediate corrective measures can be taken. Consider adding an insecticide to your planned fungicide applications in corn or soybeans. Any applications this time of year are about preserving yield potential.

Long-term corrective responses to insect and/or weed issues may require changing crop rotation or tillage strategies. Tillage can help manage the disease inoculum that will be present in the soil bank next year, while it can also be a useful tool in managing the weed seed bank in the field.

When you’re walking your corn fields as harvest approaches, Bakken recommends doing a pinch test to assess stalk quality.

Simply pinch the stalk between your thumb and forefinger in the lower portion of the plant and count how many of them collapse easily. Take counts on 10 plants in a row in random parts of the field to come up with a percent of plants that exhibit issues. Fields with a higher percentage of collapsed stalks should be scheduled to harvest early, even if that means having to dry some corn.

Checking for problems throughout the growing season is central to AgVenture’s Maximum Profit System (MPS) strategy. As part of the MPS approach, an AgVenture Yield Specialist (AYS) supports farmers every step of the way, performing a variety of vital functions:

  • Putting together a detailed cropping plan
  • Walking behind the planter to ensure proper seed placement
  • Evaluating crops in-season
  • Developing a pre-harvest plan to maximize yield
  • Taking tissue and soil samples to assess nutrient deficiencies
  • Recommending rescue treatments

“Doing things like scouting and assessing plant health can contribute to a more successful harvest,” Bakken said. “In today’s ag economy, you need to do everything you can to maximize yields. MPS can help you grow a better crop.”