DON'T LET THESE 3 LATE-SEASON THREATS CLIP CORN YIELDS

Key points

• Strong corn yields are in reach if farmers finish the season strong.
• That includes making sure corn has what it needs to maximize grain fill.
• Protecting against premature plant death and pursuing a timely harvest are also key.

Planting conditions were far from perfect in AgriGold Agronomist Nick Frederking’s territory of southern Illinois, but he says adequate rains have helped compensate for compacted corn roots. If rain continues to fall and farmers work to help the crop finish strong, he expects them to bring in good corn yields. 

“We want to start strong, and we want to finish strong,” says Caleb Traugh, a crop consultant covering the tristate area of Georgia, Alabama and Florida. He cautions against yo-yo agronomy, where input investment fluctuates alongside market prices. “Often, it’s the top 30 to 50 bushels per acre of a corn crop that represent farmers’ profit. Cutting corners can cost them top-end yield and tighten profit margins.”

To finish the season strong, they advise protecting against the following threats.

1. Decreased kernel weight

The AgriGold lineup has corn hybrids that flex in different ways — by girth, length and depth.

Kernel-depth-flexing hybrids build yield by putting a tremendous amount of weight in each kernel. This flex type needs moisture late in the season to maximize yield potential.

Unless a farmer irrigates, there’s not a lot he or she can do to control moisture. But farmers can control the amount of nitrogen available to that plant. “Late-season nitrogen loss compromises kernel depth,” Frederking says.

In Traugh’s area, irrigation is common and an important tool for filling kernels. He cautions against cutting off irrigation too soon.

“At the beginning of R5, only about 50% of the dry matter has accumulated inside kernels,” Traugh says. “Farmers shouldn’t terminate irrigation until they’re sure there’s enough moisture in the soil to carry the crop all the way to full black layer.”

Full black layer is an important distinction for Traugh. “The corn ear matures from the top down, and it can take a week to get each kernel on an ear to black layer,” he explains. 

2. Premature plant death

Disease or weather threats resulting in premature death can also limit crop prospects late in the season. This year, Frederking is concerned about gray leaf spot, northern corn leaf blight, southern rust and tar spot. Fusarium crown rot and anthracnose stalk rot are also threats after a wet and cool start to the season left corn vulnerable to infection. 

“As the corn plant starts to experience stress from these diseases and stalk rots, the growth hormone ethylene will start to rise,” Frederking says, likening it to a stress hormone in people.

A post-tassel fungicide application helps the plant maintain a healthy hormone load and suppress ethylene levels, Frederking explains. That, in turn, extends grain fill. A fungicide application can also help maintain stalk integrity, helping farmers bring in more corn yield per acre.

“With extended hours of leaf wetness in many areas across the country this season, we want to shore up plant health and make sure we don’t have diseases like southern rust move in at the tail end of the season,” Traugh says. “If the potential is there for high-yielding crops, make sure you’re doing all you can to keep it healthy all the way to the finish line.” 

3. Late harvest

It can be tempting to leave corn in the field to dry down, but that can trim yield. “Once black layer occurs, yield never goes up,” Traugh observes. He encourages farmers to scout fields and determine harvest order.

This also gives farmers an opportunity to evaluate their current management program and seed selections, helping them to prepare for the next growing season. Traugh encourages farmers to get out of the combine when they encounter really good or really bad areas of the field.

“I like to drop a pin on those points in the field and come back and pull some soil samples,” Traugh says. “These spots can contain valuable lessons. I’ll examine the components of yield in those locations to see if there’s something I should change for next year or if there’s something I can mimic across my entire farm.”

As yields come in and farmers reflect on hybrid choices, Frederking says it’s important to understand hybrids flex in different ways and at different times. “That’s why it’s so important farmers plant different ear flex types on their farms,” he says. “It gives them more control over something they don’t have control over — the environment. It spreads their risk.”

A timely harvest also allows for fall fieldwork and soil sampling that pave the way for a strong start to the 2025 season. It also helps fend off the mistakes that can occur when harvest is rushed.

As farmers head into the home stretch, Traugh has this advice: “Don’t let your foot off the gas until the corn crop is mature. Pay attention to which fields are responding to higher management and prioritize your input investments accordingly.”

For support helping your corn crop finish strong, reach out to your local AgriGold agronomist or district sales manager.