ASK THE AGRONOMIST BLOG

Growers in the Midwest considering another corn-on-corn year may wish to consult their local agronomist or university extension specialist before planting. According to the 2022 Regional Corn Rootworm Monitoring Network Summary issued by the Corn Rootworm IPM Regional Working Group, corn rootworm populations are anticipated to be high again in areas of Iowa, Wisconsin, Minnesota, Michigan, Nebraska, Illinois, North Dakota, South Dakota, Nebraska and Kansas. These states are at an elevated risk as they produce a lot of corn-on-corn acres, and findings show that rootworm is becoming more resistant to the Bt trait.  

The report highlights, “Western corn rootworm (WCR) and northern corn rootworm (NCR) continue to dominate as economic pests throughout the U.S. and Canada … Recently, high corn rootworm populations and the development of resistance to Bt corn hybrids in some areas has sparked greater interest in scouting and alternative management of corn rootworms.”

Stine^® agronomists are on heightened alert as they have monitored the rootworm crisis in their regions and continue to spread word of the potential for yield loss if not properly managed. According to the Crop Adviser Institute, rootworms cause more than $1 billion in damage and control costs annually in the U.S..

“With each passing year, we see the rootworm population increasing throughout the Corn Belt,” says Tom Larson, Stine’s director of agronomy. “Unfortunately, as we know well, these pests can devastate a crop. If you haven’t started planting yet, it’s not too late to consider a switch to soybeans on fields that experienced high rootworm pressure last year. If you’ve already planted corn-on-corn this year, talk to your local agronomist or extension expert to discuss what can be done in-season to slow the spread.”

2022 Findings
According to the 2022 results, 38% of sites tested exceeded the trapping threshold. The report notes, “For corn, the trapping threshold is 2 beetles/trap/day, regardless of species. For soybean, the trapping threshold is 1.5 western corn rootworm/trap/day; no soybean sites exceeded the threshold. These trapping thresholds indicate that the grower should consider switching up management practices the following year, because adult populations indicate that egg-laying in the field will likely result in severe larval injury the following year if corn is planted.”

Other report findings concluded western corn rootworm is the most dominant species throughout the Corn Belt but populations of northern rootworm are increasing, and fields with a history of corn rootworm are likely to have continuous issues with populations in the future. Of the sites that exceeded the trapping threshold, at least 59% were in continuous corn.

The most common issues reported in infected fields included goosenecking/lodging, high beetle populations or a combination of the two. Another reported issue was resistance to the Bt trait, which is problematic as growers have relied on the trait to suppress populations in difficult fields for  several years.  

“These findings align with what experts have been warning growers about,” says Larson. “Corn rootworms are not to be taken lightly. If it’s a problem one year, it will be a problem the next.”

Scouting tips
There are two types of corn rootworm prevalent in the Midwest — Western and Northern. Both are capable of laying eggs that can overwinter in the soil, so early-season scouting should include digging below the soil to check the roots of the plant. Later in the season, as they transition from larvae to adult rootworm beetles, they can be found directly on the plant as they feed off the leaves and silks as adults. This can greatly affect pollination during silking. 

“Early in the planting season, you’ll want to scout for the rootworm larvae by digging the soil around the corn plant,” says Larson. “Iowa State University Extension and Outreach has some great guidance for sampling, including the ‘float test,’ which involves filling a bucket of water and placing the soil and roots directly into the bucket so the larvae float to the top. This can help you detect any root damage to the plant.”

Iowa State also has an interactive node injury scale, which can help growers decipher the level of damage caused by corn rootworm larvae.

Later in the growing season as plants near silking and pollination, growers should be on the lookout for adult rootworm beetles. Western corn rootworms — the most commonly reported — are typically yellow or green and have black striping on their wings. Northern corn rootworms are light green or brown with no distinguishable marks. There are also Southern corn rootworm beetles that aren’t as common in the Midwest. These are yellow and green and have black spots on their backs.

“If you’re scouting for adult beetles, you’ll want to consider the time of day,” says Larson. “Research shows beetles are more active in the morning or late afternoon as they feed on silks and leaves, so it’s best to scout during their most active times.”

In addition to scouting, growers can employ sticky traps, which can help determine the amount of infestation. Sticky traps were one of the methods used by the Corn Rootworm IPM Regional Working Group for their 2022 findings report.  

Mitigation
“It’s clear that back-to-back corn-on-corn is an instigator when it comes to adding to the corn rootworm problem,” says Larson. “Crop rotation will continue to be critical in controlling populations.”

If crop rotation isn’t a viable strategy this year, growers need to prioritize scouting throughout the growing season. If rootworm larvae or beetles are detected, the next step would be to examine the level of infestation. From there, having a conversation with an agronomist or local extension expert can help determine next steps. One in-season strategy they might recommend is a soil- or foliar-applied insecticide. While it’s not the end-all strategy, it can help control the population throughout the important pollination stage.

“The biggest action growers can take is to plan ahead,” says Larson. “What you can do in season is minimal, so growers need to spend time discussing crop rotation and what traits make the most sense to plant next year. We know Bt traits are showing some signs of resistance, but there are likely other options growers haven’t discussed with their salesperson. Stine has an entire lineup of  Agrisure Duracade^® brand corn, for example, which has proven effective in mitigating corn rootworm. It’s definitely worth the conversation.”

One consideration to keep top of mind when discussing future strategies, according to the 2022 report, “Extension professionals do not recommend using multiple tactics to manage corn rootworm as research demonstrates no yield benefit, no reduction of larval feeding injury, and no reduction in adult emergence when both a Bt-rootworm hybrid and soil-applied insecticide are used. Furthermore, multiple management tactics could hasten resistance development.”

For more tips on preparing your fields for corn rootworm infestation this year and next, contact your local sales rep. Stine can help you maximize the potential of each and every acre by keeping corn rootworms at bay.

Planting is underway for a few states in the U.S. The April 3, 2023, Crop Progress Report notes corn planting has started in Texas, North Carolina, Kentucky and Kansas. In Texas, it’s 57% complete, which is slightly above average for this time of year. For the others, the season has just kicked off. In the rest of the U.S., planting is likely a few weeks out or more, especially for growers in the upper Midwest, where states like Minnesota, North Dakota and South Dakota have received persistent heavy snowfall this spring. Regardless of your planting outlook, knowing the right time to hit the field is critical.

“While there are benefits of early planting, you should never rush or you may put your crop at risk early on,” says Bill Kessinger, technical agronomist for Stine. “Issues like imbibitional chilling, uneven emergence or sidewall compaction could limit your crop’s ability to thrive during the growing season. Even if your neighbors have started, take the time to check your soil and the extended forecast to make sure it’s the right time for planting.”

Here are some helpful considerations from our expert agronomy team.   

The benefits of early planting

Beating the summer’s heat is one of the main benefits of planting early. The earlier you plant, the more time your plants will have to emerge and mature before the high temperatures are here to stay.

“This is especially important for corn plants as extreme heat will affect pollination and pollen shed,” says Kessinger.

According to the University of Nebraska Institute of Agriculture and Natural Resources, prolonged periods of heat can reduce pollen production, particularly with consecutive days that reach 95 degrees Fahrenheit or more.

In soybeans, planting early allows the plants to mature at a more optimal time and the soybean canopy to form earlier. Michigan State University Extension suggests, “Early-planted soybeans produce a larger crop canopy earlier in the growing season, which leads to better utilization of the solar radiation and soil moisture available during the growing season.”

After emergence, experts note soybean cotyledons are also more resistant to freezing temperatures than corn as they have thicker tissue.   

The pitfalls of early planting

“For corn, planting into cold, wet soils can increase the risk of uneven emergence,” says Tony Lenz, technical agronomist. “If corn sits in the ground longer than it should, the plant is forced to live off the energy and nutrients stored in the seed, which doesn’t allow for a good start. This can impact the crop during the early vegetative stages and weaken its root structure in the long haul.”

Lenz stresses that growers need to remember corn imbibes 30% of its weight in water before it germinates. “If it imbibes cold moisture within 24-48 hours after planting, it can severely disrupt the germination process, leading to severe issues to the developing embryo. This is called imbibitional chilling, and it can be detrimental to yield,” he adds.

Imbibitional chilling occurs when there’s a dip in the water temperature being imbibed by the seedling, which is why it’s crucial to monitor the extended weather forecast before planting.

“This is especially important to consider with the recent cooler temperatures and heavy moisture we received and are forecast to continue to receive throughout much of the Midwest,” says Lenz. “Imbibational chilling can lead to a corkscrew effect of the mesocotyl, which can result in death of the seedling.” 

Similar to corn, if soybeans are planted in cool, wet soil, they will experience emergence issues. Soybeans are also susceptible to chilling injury.

“Chilling injury compromises the seed coat — or that protective layer — of the soybeans,” says Lenz. “This leads to delay in emergence, or uneven emergence and, ultimately, poor stand. That said, soybeans are a bit better equipped to handle inconsistent emergence compared to corn.”

Other considerations

Growers also need to consult with federal crop insurance guidelines for replanting. According to the University of Minnesota Extension, “Farmers with federal crop insurance will lose replant coverage if they plant before the earliest allowable planting dates specified by the United States Department of Agriculture (USDA) Risk Management Agency.” They add that this is true even if growers need to replant due to factors other than freeze damage or poor emergence. 

Sidewall compaction is another consideration with early planting, especially when seed furrows are made into high-moisture soil.

“Planting into soil that’s too wet can affect emergence and plant stand,” says Kessinger. “If the seed is compacted into wet soils, you run the risk of root growth problems, where the roots might grow sideways versus straight down. The same is true if you plant too shallow. You need to ensure the moisture level of your field is optimal for planting and your planter is adjusted for proper seed-to-soil contact before putting in corn or soybeans.”

The answer to the planting timing conundrum?  

There is no right or wrong answer. It all boils down to your situation and extended forecast. A few things Stine agronomists can always agree on when it comes to planting are:

• Ensure soil temperatures are a consistent 50+ degrees Fahrenheit for more than a few days.
• Check the extended weather forecast and avoid planting when a cold rain is anticipated within 24-48 hours after planting.
• Test your soil moisture. Check the soil at the depth you intend to plant to examine the texture of the soil. Iowa State University Extension and Outreach provides great tips for determining the moisture levels of your soil.
• Avoid sidewall compaction by checking moisture levels, avoiding planting too shallow (we recommend a minimum of 2 to 3 inches for corn and 1.5 to 2 inches for soybeans), and not applying too much downward pressure on the press wheels of your planter.
• Know the date restrictions for federal crop insurance.
• Consult your local Stine agronomist or university extension expert for local recommendations.

To connect with your local Stine agronomist or sales expert for planting recommendations, visit Find Stine. Here’s to a safe and productive planting season!

In farming and life, most people avoid striking out as much as possible. The opposite is true for fourth-generation farmer Brent Beichley. Strikes are his passion.

When the season for growing corn and soybeans is over, Brent can be found knocking down pins as part of a weekly bowling league and team that goes to state and national tournaments. Just like a love for farming has been passed down through the generations, his grandmother inspired him to take to the lanes.

“When I was 5 years old, my grandma bought a 5-pound bowling ball for me,” Brent explains. “She said, ‘We’re going to teach you to bowl.’ Growing up, she was my biggest fan.”

Ever since, Brent’s been seeking coveted strikes and settling for game-saving spares on the hardwood lanes.

Today, bowling remains a family affair for the 42-year-old farmer who lives a few miles northeast of Marshalltown, Iowa. Brent regularly bowls with his uncle Lynn, and his dad Duane, who lives in the Ozarks, joins the team for the state and national tournaments. His son Jayden is a high school freshman and bowls on the varsity team, and his daughter Jenna bowls when she can spare the time between basketball and volleyball. While Brent’s wife Susan isn’t a bowler, she’s always in the crowd rooting for the family’s teams.

The sport parallels Brent’s philosophy with farming. “I’m always working hard and having fun trying to improve things," he says. "I like it when the previous generation of farmers tells me that I'm doing a good job and to keep it up."

Just like his grandparents cheered him on to do his best in bowling and other sports, having those cheerleaders in agriculture is gratifying.

Brent loves the opportunity to frame up conversations around agriculture whenever he has the chance.

“Stine is our team sponsor, and they supply us with our bowling shirts,” says Brent, who began growing with Stine in 2020. “My dad and I also have bowling balls with the Stine Seed Company logo on it and Kirk Kintz — our Stine Seed rep — is getting a ball made for another member of our league. Having the Stine brand on our shirts and balls is a great conversation starter. People will ask me what the logo stands for, and it’s always a win-win when I get to share things about agriculture, farming and a brand I proudly represent.”

He adds, “Stine is such a great company and family, and I love to be raising soybeans for them. I thank Kirk and the whole Stine family for going far beyond just selling us seed and being a partner for us in the fields and at the lanes.”

Note: Our Ask the Agronomist content focuses on the agricultural innovation that drives our business, but we also want to highlight the stories of our customers, their passion for life and the industry that we all love. If you have a Stine grower story to share, contact marcom@stineseed.com.