Tar Spot

Iowa Farmer Battles Today's Pests While Eyeing Tomorrow's 'Mean Sixteen' Threats

Fri, 12 Dec 2025 18:55:16 GMT

For Worth County, Iowa, farmer Sarah Tweeten, the list of high-priority agronomic threats isn’t a political abstract — it’s a harsh reality she deals with every season.

Farming with her parents, Brian and Julie, and her uncle Roger, Tweeten has been steering the partnership toward more resilient cropping practices since joining the operation in 2021. This includes shifting from conventional tillage to strip tillage and splitting nitrogen applications.

The changes are part of a broader mindset: Protecting yields today from weeds, disease and insects while aggressively preparing for the next generation of agronomic threats. This forward-thinking approach is what led Tweeten to Washington, D.C., earlier this week as a Farm Journal Foundation farmer ambassador to help introduce a new report: “ The Mean Sixteen: Major Biosecurity Threats Facing U.S. Agriculture and How Policy Solutions Can Help. ”

Today’s Battles and Tomorrow’s Warnings
Researched and developed by Stephanie Mercier, PhD, the report takes an in-depth look at 16 significant pest issues U.S. farmers face now or could realistically in the future.

Tweeten is already battling a couple of the problems that underpin the urgency behind the research. For example, Palmer amaranth (pigweed) is gaining ground in her fields and across Iowa. The pervasive broadleaf weed can drastically reduce yields, with studies showing corn yield reductions between 11% and 91% and soybean yield reductions of 17% to 68%.

“We’ve struggled with pigweed as it continues to establish more resistance to our herbicides in our toolkit,” Tweeten says.

Two additional agronomic issues the report details include:

1. Asian Soybean Rust. First detected in the U.S. in Louisiana in 2004, this fungal disease has spread to southern states like Georgia and Mississippi. Scientists warn that warming winters could enable its migration to the Midwest, adding to existing disease pressures.

2. Corn Ear Rot. It can lead to aflatoxin production, making corn unmarketable and posing risks to humans and livestock. Aflatoxin is an issue Pickens County, Ala., farmer Annie Dee says is an ongoing problem for corn growers in her area.

“If we have aflatoxin, it can be impossible to sell the corn,” says Dee, also a Farm Journal Foundation Farmer ambassador.

A more recent threat she references is the impact of Highly Pathogenic Avian Influenza (bird flu) on local poultry farms.

Since January 2022, HPAI has been confirmed in a commercial or backyard poultry flock in all 50 states.

(USDA)

“An important market for us is poultry feed meal, so that’s a constant worry. The trickle-down effect is if we can’t move our corn then we can’t meet our financial obligations,” Dee adds.

Despite agricultural R&D offering a high ROI — $20 in benefits for every $1 spent — the Farm Journal Foundation report notes public funding for ag research has been declining over the past two decades.

“Farmers urgently need sustained support for aflatoxin research and prevention because these risks threaten our yields, our markets and the trust consumers place in American agriculture,” Dee says.

U.S. public spending on ag research and development has been falling for two decades.

(USDA-ERS)

African Swine Fever Has ‘Devastating Potential’
Looking to the future, Tweeten says she is concerned about African swine fever (ASF) and its potential to impact crop farmers as well as hog producers. The highly contagious swine disease hasn’t been detected in the U.S. mainland, but it isn’t far away. ASF has been confirmed in the Caribbean countries of Haiti and the Dominican Republic, roughly 700 miles from Miami, Fla.

“Being a farmer from Iowa, where we have probably eight times the amount of pigs as we do people, an outbreak of ASF would be just devastating to our state,” Tweeten says.

Hogs are among the biggest customers for the corn and soybeans Tweeten and her family grow. If African swine fever were to shut down hog production or exports, it wouldn’t just be a blow to livestock producers – it would hurt the entire agricultural community, she contends.

Read about 5 livestock diseases that could impact U.S. food security and economic stability.

Food Security Is National Security
When it comes to justifying funding for ag research, Tweeten knows there’s competition for every federal dollar. But she believes agriculture deserves a front-row seat — not only because of its economic weight and impact on farmers, but because of its role in national security.

“There’s that argument that food security is national security,” she says. “If there’s one thing COVID made us aware of, it’s that a disruption to our food chain can be terrifying, quite frankly.”

The pandemic made consumers and policymakers more aware of supply chain vulnerability. In 2020, the shock to the supply chain came from a human disease and logistical bottlenecks.

(Sarah Williams Photography)

Next time, Tweeten says, the disruption could just as easily come from animal or plant disease — whether African swine fever in hogs, Asian soybean rust or some other pathogen in crops. She worries about scenarios where farmers could face a fast-moving disease or crop pest while critical tools are still hung up in regulatory delays.

Her message: Farmers need a full toolbox, not one that’s half-built by the time a threat arrives.

“Ag needs to be in a good position when these sorts of emerging diseases and pests come into the country,” she says, “to have the tools in our toolbox ready for farmers to pull out.”

About the Farm Journal Foundation
The Farm Journal Foundation is a farmer-centered, non-profit, nonpartisan organization established in 2010. It works to advance agricultural innovation, food and nutrition security, conservation, and rural economic development.

Southern Rust Set To Take Big Bite Out Of Midwest Corn Crop?

Wed, 27 Aug 2025 21:56:59 GMT

If one picture is worth a thousand words, then the video Iowa farmer Dan Striegel shot last week must be worth thousands more. In the video, Striegel is shown harvesting a field of emerald-green corn enveloped in a cloud of orangish-red southern rust.

“We were just getting that field opened up, and I looked over and saw that dust boiling up out of the chopper, so I shot the video,” Striegel says.

Southern Rust? Never heard of her.
What Cheer, Iowa. USA. #pftour25 #harvest25 pic.twitter.com/tiIsUc2CHl
— Dan Striegel (@djsinseia) August 21, 2025

To date, Striegel’s video has garnered more than 48,000 views on X, formerly Twitter.

“We’re in southeast Iowa, Keokuk County, and I think the southern rust is as bad here as it is anywhere,” Striegel adds. “Every field you walk in, if you’re wearing a white T-shirt, you’ll come out of there red.”

A Red Path Of Disease Mars The Midwest

Expect to see more red T-shirt-clad farmers walking out of cornfields across the upper Midwest, based on what the Crop Protection Network (CPN) southern rust map is showing.

The CPN continually updates its online, interactive map showing the counties by state where southern rust infections are confirmed. Now, in late August, the counties look like red steppingstones. They form a checkered path from southwest Michigan through northern Illinois and Indiana, into southern Wisconsin, across all of Iowa and nearly two-thirds of the way across Nebraska. Eastern South Dakota is also lit up with a string of red counties, as are parts of southern to central Minnesota.

The amount of southern rust present in the upper Midwest is worrisome to Ken Ferrie, Farm Journal Field Agronomist. In severe cases, the disease can wipe out 45% of the yield potential in a field, according to the CPN.

“At most, one in 10 growers in northern Iowa and Minnesota have seen the kind of southern rust some of them are seeing this year,” says Ferrie, who was working last week with corn growers in both states.

“It was a problem in probably eight out of every 10 fields I was in, and they’d all been sprayed at least once,” he says. “Minnesota has a corn crop that’ll knock your socks off – yield potential of 250, 270. I encouraged every grower to spray their field a second time except for two fields. One had been knocked down by hail, and the other had a hybrid that was clean.”

I spoke with a good friend of mine from Iowa yesterday that is an agronomist and farmer. He said the southern rust in corn across Iowa and much of the Midwest will take 9 to 12 bushel/acre off corn yields on average from what his team and himself are seeing. pic.twitter.com/Ad1VJ9oQBg
— Captain Cornelius1 (@ISU145) August 26, 2025

Hybrids Have Little To No Resistance To Southern Rust

A combination of early-season moisture, heat and wind formed the perfect storm for southern rust this season, allowing the disease-causing fungal spores (Puccinia polysora) to move from southern climes up to the Midwest, according to Kurt Maertens, BASF technical service representative for eastern Iowa and western Illinois.

“We’ve seen it all – southern rust, tar spot, northern corn leaf blight, gray leaf spot. Our corn has been inundated with all these fungal diseases, and we started seeing them early,” says Maertens.

If there’s a silver lining to southern rust, it’s that it does not overwinter in corn residue like tar spot does. But like tar spot, southern rust takes advantage of hybrids that have no built-in resistance. For many growers, that was an Achilles heel this season.

“When you’re dealing with a 117-day hybrid like they grow in southern Illinois, Tennessee, and Kentucky, you don’t grow corn that doesn’t have good southern rust resistance, because they deal with it every year,” Ferrie notes. “When you move to Minnesota, and you’re planting 102- to 95-day corn, you’re probably not going to find hybrids with southern rust resistance.”

Striegel says that was true for his neighbor’s cornfield, which he custom chopped for silage. “That field had two hybrids in it, one was worse than the other, and the field had been sprayed with a fungicide,” he says.

He adds that he also sprayed his own cornfields with fungicide, but they are still inundated with southern rust.

“We’ve had southern rust before, and it’s not usually something we have to worry about, but this is really bad,” Striegel says. “I’m standing on my deck looking at the cornfield next to my house, and you know, all of the leaves from the ears down in that field are covered with it.”

Southern rust is real in eastern Nebraska. Fungicide 3 weeks ago, 2nd app today with some potassium acetate pic.twitter.com/WZubU6IBwz
— Trent Mastny (@TrentMastny) August 21, 2025

How Late Is A Fungicide Application Still Worthwhile?

Ferrie says the fields he scouted last week were at late R3 to early R4 and had already been sprayed with fungicide at least once, but the disease was rebuilding.

“Any field where farmers had sprayed two weeks previously, the southern rust and northern corn leaf blight, to a lesser degree, were coming back, especially the southern rust. It was resporating,” he says.

The intense disease pressure from southern rust, tar spot and others have kept fungicide use at high levels this season, despite poor commodity prices.

“Because of that [amount of disease pressure], we have seen increased demand for our fungicides this year,” says Maertens, who encouraged customers to get applications made at the beginning of tassel.

Maertens says he has fielded a lot of questions this summer from farmers, asking how late they could go with a fungicide application and still benefit.

“Our recommendation is to get in front of disease,” he says. “Generally, we stop applications before we get to dent (R5). That’s not to say a later application can’t have some benefit, but our best results have been before infection was able to take place.”

Southern rust is a yield enemy farmers routinely face in the Southeast, reports corn yield champion Randy Dowdy, Valdosta, Ga. He participated in the Pro Farmer Crop Tour last week and said on U.S. Farm Report he believes many Midwest farmers still have time to address disease.

“We need to implore the fungicides, the technologies out there and get after it and protect this crop, especially that crop that still has not reached dent,” he says.

Farm Journal Field Agronomist Missy Bauer likes to see farmers complete their fungicide applications on the front side of dough (early R4). “Once we get to early dent, I think it’s a little more challenging to get the payback consistently, though we’ve applied at early dent (R5), and seen a nice response,” says Bauer, who is based in south-central Michigan.

Under the tough disease pressure farmers are facing this year, Bauer is telling growers to scout fields and evaluate what growth stage their crop is in before they walk away or pull the fungicide trigger one last time.

She adds that farmers need to check the label to make sure the product used is able to address southern rust effectively. She describes these as “Cadillac” products containing the newest chemistry.

“When it comes to some of these diseases, especially southern rust and tar spot, I do believe a little bit of a Hail Mary pass can be effective,” she says. “Will it be as effective as an application you could have made on a more timely basis? Well, no, you could have made more money doing it timely, but you’re still protecting bushels and gaining ROI at the end.”

Ferrie adds that farmers might want to do the late-season fungicide application to keep their corn crop standing until they can put their harvest plan in place.

“Be doing the push test to check stalk quality,” he advises.

Southern Rust/Silage Alert!!

Southern Rust has been aggressively advancing in many fields, especially those without a fungicide treatment. In some situations the plants are shutting down prematurely and plant material is senescing rapidly.

While we typically want to get down… pic.twitter.com/aK3hGgZE19
— Pioneer Troy (@deutmeyer_troy) August 26, 2025

Striegel says some of the farmers around him are heading to fields to harvest their silage corn sooner than later, because of standability concerns. “Some of this corn got planted early, and we had a lot of heat. The crop matured quickly, and the diseases are kind of shutting it down. It’s just dying out, and guys are going to go get it,” he explains.

That’s the strategy Ferrie encourages farmers to use in regular production corn, too.

“Harvest the fields most at risk first. But if a field of corn goes down, go combine the fields where the corn is still standing and come back to that one later,” he recommends.

The reasoning is you don’t want to risk more corn going down while you’re harvesting the field of corn that already has.

“While I was driving through Iowa last week, I kept thinking that if I built corn reels to pick up down corn I’d bulk up my inventory, because I know where they’re going to get used,” Ferrie says, only half joking. “Yes, harvesting corn at 25% moisture is expensive, but down corn will kick your butt.”

Your next read: Revenge Applications: Why They Don’t Work, Cost You Money and Bushels, and Are Frankly Illegal

How Pro Farmer 2025 Crop Estimates Compare and Contrast With USDA Expectations

Fri, 22 Aug 2025 20:35:41 GMT

As more than 100 crop scouts traversed dirt roads and two-lane highways, stopping dozens of times to sample corn and soybeans in seven Midwest states, they gathered insights to answer the question on many farmers’ minds this week: How would the Pro Farmer estimates compare to the numbers USDA-NASS released August 12?

The answer: Pro Farmer found a big corn crop but one that’s currently positioned to average 182.7 bu. per acre – 6.1 bu. below USDA’s 188.8 bu. projection.

“When we put the yield estimate out, it comes with a plus or minus 1% for corn and a plus or minus 2% for soybeans, and that’s because we know things can change yet,” says Chip Flory, host of AgriTalk and lead scout on the western leg of the tour.

“The other thing is the yield models that we use give us a range, and then, based on conditions, we can move within that range with the yield estimate that we’re going to pull,” he adds.

With that perspective in play, here’s how the Pro Farmer and USDA estimates compare:

Pro Farmer Corn Estimate (+-1%): 16.042 to 16.366 billion bushels; 180.9 to 184.5 bu. per acre average
USDA Corn Estimate: 16.7 billion bushels; 188.8 bu. per acre average

(ProFarmer)

Disease Pressure Across The Midwest Is Concerning
The 2025 growing season has been marred by heavy disease pressure in many of the corn and soybean crops Pro Farmer scouts evaluated this week.

It was an issue Lane Akre says showed up repeatedly in corn and soybean fields from the get-go, as tour scouts fanned out to check 2,000-plus fields across seven states: Illinois, Indiana, Iowa, Minnesota, Nebraska, Ohio and South Dakota.

“We know disease can speed up the maturation of plants, making it difficult to keep them healthy long enough for optimal grain fill before harvest,” says Akre, Pro Farmer Economist and lead scout on the eastern leg of the tour. “We are concerned diseases like southern rust and tar spot could negatively impact corn yields in some of these states during the next few weeks.”

Soybeans Could Be the Star of the Season
USDA’s August estimate for the national soybean yield average is just slightly above what Pro Farmer scouts found in fields this week. Pro Farmer places the soybean yield average at 53.0 bu. per acre, with a total crop size of 4.246 billion bushels

By comparison, USDA expects soybeans to average a record high 53.6 bu. per acre, with a total crop of 4.29 billion bushels.

Pro Farmer Soybean Estimate (+-2%): 4.161 to 4.330 billion bushels; 51.9 to 54.1 bu. per acre

“One of the questions heading into the tour was whether the soybean crop could live up to the lofty expectations a lot of people have for it, and we found that it does,” Akre says. “There’s a massive crop out there in fields. We’re just hoping it can hold on until harvest – and outpace the disease pressure out there – to deliver on those big yields.”

Corn and Soybean Yield Summaries
Pro Farmer and AgWeb reported extensively throughout the tour — the highs and lows of each crop in each of the seven states. Here are summaries from each state. Click on the links to learn more details.

Illinois: Scouts reported an Illinois corn crop that looked lush from the road, but once they picked ears and pulled back husks, most described finding an average to above-average crop – not the record yield estimate USDA reported on August 12.

“The Illinois corn crop just wasn’t what we’d hoped,” Akre says. “USDA is anticipating a 1.7% jump from a year ago, and we’re actually down 2.2%.”

Indiana: Wet conditions from rain, fog and heavy due is causing some unevenness in Indiana corn and soybeans. Still, the state’s corn crop posted a yield number that came in 3.35% higher than its 2024 number.

From disease pressure to too much rain, some scouts found a solid soybean crop in Indiana, while other routes exposed extreme variability. Overall pod count numbers were down 2.30% from 2024.

Iowa: Scouts spent two days in the state gathering dozens of samples to gain insights and project yield estimates. Despite challenges from disease pressure, scouts reported a big corn crop with significant potential. Their estimates put the Iowa crop up 2.93% over 2024, and up 6.4% versus the three-year average.

“This Iowa crop has a very, very strong ear count, great grain inches — just a very consistent equation putting that corn yield together,” reports Emily Flory Carolan, Pro Farmer Crop Tour data consultant.

For soybeans, scouts found a massive crop, up 5.49% in the number of pods as compared to the 2024 crop.

Minnesota: The corn crop in Minnesota is currently heading for a record yield this season, if it can outpace disease pressure. Scouts recorded the longest grain inches in the corn there that have ever been measured in the tour’s history.

“That’s definitely what pulled up that yield average for us,” Carolan says.

Soybeans also show tremendous yield potential in Minnesota. Pod counts were up 20.38% this week versus 2024 counts, and up 19.9% versus the three-year average.

Nebraska: Adequate moisture is pulling up corn yields in the state this season, with some tour routes reporting 8% to 10% increases compared to 2024 and 2023. The much-improved corn yield estimates were a welcomed change, scouts say, after seeing corn there struggle in two back-to-back years of drought.

Soybeans also are promising big yield results, with pod counts up 15.0% this week over the 2024 estimate.

Ohio: Heavy rains last spring meant many farmers either got a late start to the growing season or they had to replant fields. The moisture extremes early on have resulted in considerable variability in fields from one end of the state to the other. Still, scouts say the Ohio crop has solid corn yield potential overall, citing possible records along some Pro Farmer Crop Tour routes.

The soybean pod factory in Ohio is going strong – with numbers up 4.66% this season over 2024 – but scouts caution a lack of late-season moisture is concerning. More rain is needed for the soybean crop there to finish well.

South Dakota: Based on USDA’s August crop estimates, scouts knew the possibility was there to uncover a big crop in South Dakota. Field estimates show record yield potential is possible , especially due to ample moisture this year that’s supported growth and development.

Soybeans might be an even better story in South Dakota this year. Pod counts came in at 15.9% above last year’s tour and well above the three-year average of 970.1 pods.

For more insights from the 2025 Pro Farmer Crop Tour:

Watch On-Demand: Pro Farmer Crop Tour Day 4 Results from Iowa and Minnesota

Watch On-Demand: Pro Farmer Crop Tour Day 3 Results from Illinois and Iowa

Watch On-Demand: Pro Farmer Crop Tour Day 2 Results from Indiana and Nebraska

Watch On-Demand: Pro Farmer Crop Tour Day 1 Results from Ohio and South Dakota

Iowa Corn Has High Potential, Illinois Crop Looks Average and Soybeans Shine in Both States

Wed, 20 Aug 2025 23:58:45 GMT

Bright orange is a great color for pumpkins but not so much for corn. Nonetheless, that was the prevailing color Brent Judisch reports seeing as he evaluated crops Wednesday morning in northwest Iowa’s Harrison County.

“Our first six or seven samples were terrible with southern rust,” says Judisch, a Pro Farmer Crop Tour scout and Iowa farmer. “We saw three fields in a row that were actually gross. I walked out of them just covered with it. After that, while we’ve seen it all day, it’s been more in the lower leaves and not nearly as drastic.”

Chip Flory, lead scout for the western leg of the tour, says the northwest Iowa crop is the best and worst he’s ever seen.

“In the snapshot that we took of it, and the measurables we saw in the field today, it is the best corn crop,” Flory reported during the tour’s nightly live broadcast.

But the disease pressure in the Iowa crop has Flory spooked.

“Disease pressure is putting a lot of bushels — a huge number of bushels — at risk,” he adds. “You can take 20, 30 bushels off of corn yield with what southern rust can do to the crop, even at this late stage in the game. It’s a dangerous crop that we’re looking at out here right now.”

Chip Flory says he was surprised to see corn that was well into R5 (dent) in northwest Iowa. “I can’t tell if it was this mature because of pressure from the southern rust, or if it was because of higher nighttime temperatures at pollination,” he reports. “I am concerned about how much disease is out here, and what it’s going to look like in another week or two.”

(Chip Flory, Host of AgriTalk)

Can The Iowa Corn Crop Still Hit A Record?
The Iowa corn results were a big shocker on Wednesday, given the amount of disease pressure scouts saw, according to Emily Flory Carolan, Pro Farmer Crop Tour data consultant.

“I would say all three districts were setting new records. They were consistently high in all measurements for corn in ear count, inches long and kernels around,” she says.

Carolan’s summary of the results scouts tallied in Iowa revealed some high yield estimates, despite the disease pressure:

*District 1 was 197.89 bushels, up 12.06% versus 2024 and up 9.89% versus the three-year average.

*District 4 was 207.25 bushels, up 5.82% versus last year and up 14.01% versus the three-year average.

*District 7 came in at 195.03 bushels, up 1.80% versus 2024 and up 6.35% versus the three-year average.

(ProFarmer)

Flory is concerned southern rust will impact standability in the Iowa crop, which he says is starting to dent in areas, and cause some of it to go down.

“I’d want to keep an eye on the stalk condition of this crop, because if this disease pressure continues, farmers are going to want to get out and prioritize fields for harvest before we get there,” he adds.

Illinois Corn Crop Looks Average
Scouts report the Illinois corn crop appears lush from the road, but once they walked out into fields, picked ears and pulled back husks, most described finding an average crop.

“We’ve seen some good corn, we’ve seen some average corn and we’ve some stuff that’s got a long way to go,” tour scout Jake Guse told U.S. Farm Report’s Tyne Morgan on Wednesday morning.

That perspective played out in the total results tallied and shared during the nightly tour meeting. Illinois corn averaged 196.19 bushels per acre, down 2.24% from last year but up 1.72% from the three-year average.

(ProFarmer)

Ninth and final stop 4 miles North of Roseville, IL. Population was very good at 34,000. The yield is 213. Kernel depth is just under a 1/2 inch. Some disease was showing up here including tar spot! Soybeans had 1778 pods in 3X3 area. #oatt #pftour25 pic.twitter.com/xAcDSxJL0q
— Darren Frye (@Frye_WSS) August 20, 2025

USDA-NASS estimates released August 12 project the Illinois corn crop will come in averaging 221 bu. per acre for the state, up 4 bushels over 2024.

That’s outside what Guse’s expectations are for the state.

“As you’re driving along the road, you can see ears that are already tipped over. I just don’t see it reaching [USDA’s projection],” he says.

Lane Akre, Pro Farmer economist and host for the eastern leg of the tour, agrees with Guse. He reports pulling several samples of corn that exceeded 200-bu. per acre as well as one that only hit 143 bushels.

“The Illinois crop just wasn’t what we’d hoped,” Akre says. “USDA is anticipating a 1.7% jump from a year ago, and we’re actually down 2.2%.”

Akre’s leg of the tour went through three Illinois counties that are typically heavy hitters for corn yields: Bureau County, Henry County and Rock Island County.

“There’s really good dirt through that area, and the farmers there are very good at actively managing their crops and what they do with fertilizer, herbicide and fungicide,” Akre notes. “We saw some poor emergence and that might’ve weighed on the samples we took.”

Soybeans Could Be the Star of the Season
Soybeans offered a better yield picture for Illinois farmers than the corn crop, Akre notes.

“We didn’t have a single sample in the state that was south of 1,300 pods in a 3’x3' square. We saw a lot of pods and a lot of potential out there,” he says.

The average counts Illinois scouts recorded was even higher than what Akre found, with an average of 1,479.22 pods in a 3’x3' square area. That is up 4.24% versus 2024 and up 12.65% versus the three-year average.

(ProFarmer)

Iowa soybean results across the three districts were equally impressive.

“This year’s crop is better than last year by far,” Greg Lehenbauer, Pro Farmer crop scout, told AgDay’s Michelle Rook. “They’ve had adequate rain across this part of Iowa almost all summer long.”

#pftour25 Day 3. Stop 2 Plymouth Co. IA. #Soybean pod count 816. @AgDayTV @FarmJournal @USFarmReport pic.twitter.com/GgmulwJ8UI
— Michelle Rook (@michellerookag) August 20, 2025

Carolan’s data confirmed the excellent soybeans that crop scouts found on Wednesday in all three districts:

*District 1 soybeans: 1,279.25 pods, up 15.38% versus 2024 and up 15.05% versus the three-year average.

*District 4 soybeans: 1,376.15 pods, up 9.73% versus 2024 and up 13.63% versus the three-year average.

*District 7 soybeans: 1,562.54 pods, up 14.37% versus 2024, and up 24.66% versus the three-year average.

(ProFarmer)

While Flory is cautiously optimistic about the Iowa soybean crop, he says stem rot and sudden death syndrome is taking root in more fields and threatening yield outcomes.

“Some of the routes through southern and west-central Iowa have seen a tremendous amount of disease issue on the soybeans, so I’ve got a feeling it’s going to look a lot different in a week than what it does right now,” he predicts. “Now, if it was September 10, that’d be one thing. But it’s August 20, and there’s still time for those bean diseases to take some yield away.”

Flory’s sentiment about what fields revealed in Iowa was shared by scout Brent Judisch.

“What it’s going to come down to here in the corn and the beans is, does the crop mature faster than the disease moves, or will disease outpace the crop?” Judisch says. “We won’t know for sure for another two or three weeks.”

Watch On-Demand: Pro Farmer Crop Tour Day 3 Results from Illinois and Iowa

Watch On-Demand: Pro Farmer Crop Tour Day 2 Results from Indiana and Nebraska

Watch On-Demand: Pro Farmer Crop Tour Day 1 Results from Ohio and South Dakota

About the Pro Farmer Crop Tour
The Pro Farmer Crop Tour is taking place Aug. 18-21, 2025. Simultaneously, the tour follows an eastern and western route, with the two culminating in Rochester, Minn. Nightly meetings in each location review daily results, scouting observations and historical comparison data. Attend nightly meetings in person or watch the nightly broadcast online at AgWeb.com/croptour .

R5 Growth Stage Holds Hidden Yield Potential

Wed, 20 Aug 2025 16:09:55 GMT

As your corn crop turns the last corner of the 2025 growing season and heads for the finish line and harvest, there is still a lot of potential yield to be made or lost in the process.

The R5 growth stage (dent) – the next to last growth stage for corn – is one of those key times in the season where your management practices and Mother Nature’s cooperation up to that point can influence harvest outcomes.

Dan Quinn, Purdue University Extension corn specialist, explains the reason: kernel dry matter content in a corn crop at the beginning of R5 is only at roughly 45% of the eventual final accumulation.

Another way to look at that – there is still up to 55% of the kernel dry weight left to be accumulated by the crop, starch that can contribute significantly to grain fill and yield.

“Therefore, if significant environmental stress (drought, nutrient deficiency, etc.) were to occur during beginning R5, significant yield losses can still occur,” Quinn writes in this online article .

Many of the newer hybrids seed companies have developed are designed to add bushels by increasing the amount of starch in kernels, according to Ken Ferrie Farm Journal Field Agronomist.

“That’s one way we obtain yield increases without raising populations,” Ferrie says.

Keying Into The R5 Growth Stage
Michigan farmer Nathan Baker addresses the importance of R5, in his most recent video, posted to YouTube on Monday .

In the video (starting at about 24 mintues), Baker is evaluating his early-April planted corn, which is starting to reach dent (R5). Of his entire 2025 crop, he says it is the most advanced field of corn he has, noting there is some disease pressure present.

“That is northern corn leaf blight. You can see it started with a lesion here, and it has spread. There’s another one. I don’t like to see that…but there’s nothing drastic,” Baker says, pointing to some damaged areas on a corn leaf.

Baker says he used fungicide to rein-in disease pressure. In some fields, he made two applications.

(Nathan Baker)

Knowing the importance of late-season grain fill is a key reason Baker says he made the investment in applying a foliar fungicide some weeks earlier.

“That’s why it’s important that we … take care of these plants late in the season and keep packing that starch in there, giving it all the nutrients and the things that it needs. It’s why I still really, really want some rain, because we can still use it to help make this corn crop better,” he says.

Baker gives a shout out to his AgriGold agronomist, Wayde Looker, for the insights he learned about the R5 growth stage.

Look For The Milk Line In Kernels
As corn moves into the R5 stage, you can start to see a distinct line near the top of kernels, which is the milk line. This line indicates the division between the dry and liquid material in the kernel.

The R5 growth stage in corn can occur approximately 30 – 40 days following silking and is defined when nearly all kernels are ‘dented’ at the crown of the kernel and hard starch or solid endosperm has begun to form.

(Dan Quinn, Purdue University Extension Corn Specialist)

As kernels harden, the line moves from the top of the kernel down to where the base attaches to the cob. Keeping an eye on the milk line’s progression is useful to corn growers who cut crop for silage or are trying to determine when to stop irrigating. It’s also helpful for growers trying to determine how much time is left before the corn reaches maturity and will be ready to combine.

Quinn says corn moves through the early part of R5 quickly and then slows as it nears physiological maturity (R6, black layer). Overall, from the beginning of R5 to maturity is about 33 days:

3 days — from the start of R5 to the quarter milk line stage
6 days — from quarter to half milk line
10 days — from half to three-quarters milk line
14 days — from three-quarters milk line to black layer

Actual time to black layer may vary depending upon the hybrid and the environment. However, this is a guide that lets you know what to expect and help you plan for harvest, Quinn says.

Your next read: Understanding Ear Flex

If You're On The Fence About Fungicide Use in Corn, Consider These 5 Questions

Wed, 23 Jul 2025 21:43:15 GMT

As Ken Ferrie evaluates disease challenges he sees in cornfields right now, tar spot comes to the top of his list of concerns.

“We’ve got a lot of areas that are picking up these 3-, 4-, 5-inch rains, and that’s where you’ll see tar spot really blast if and when it takes off,” says Ferrie, Farm Journal Field Agronomist.

The disease started showing up in central Illinois corn the last week of June this summer, similar timing to what occurred in 2021.

“Last time we had tar spot in June was in 2021, and it really butchered us before it got done,” Ferrie recalls.

While the disease is showing up in Illinois and a handful of other states, the impact so far has been low. But that could change quickly. Ferrie is especially concerned what will happen, now that pollination is almost over for most Midwest corn crops.

“It seems like after pollination, corn gives up some of its disease resistance,” he told Farm Journal’s Tyne Morgan and Clinton Griffiths during their recent podcast, Unscripted. Watch it here:

“The disease pressure really ramps up after pollination compared to pre-pollination, when that corn plant kind of switches to making grain versus being protective,” he says. “I do anticipate that we’ll see a lot more tar spot pressure here, especially in our wet areas, because of the heavy fogs, the humidity in the morning, the wet leaves.”

Charting Average Daily Humidity Can Help
Missy Bauer is also nervous tar spot could take off in Michigan fields this season. She is encouraging farmers to keep an eye on the average daily humidity levels for their area.

This is a humidity chart Farm Journal Field Agronomist Missy Bauer put together, showing what farmers in south-central Michigan, near Coldwater, can expect through July 31. Notice that the data is averaging below what the area saw in 2021 — a huge year for tar spot — but above what occurred in 2022.

(B&M Crop Consulting, Coldwater, Mich.)

“Universities have found when average daily humidity is above 75%, corn crops are at risk,” says Bauer, Farm Journal Field Agronomist and owner of B&M Crop Consulting, Coldwater, Mich.

You can find the average daily humidity information for your specific area online via Weather Underground and other weather station resources.

She says economic data is telling her that a single pass of fungicide at R1 will pay for itself in corn that’s at risk for tar spot. “The data is very supportive of making that first pass, no problem,” she says.

The same data shows a double pass of fungicide often delivers a return-on-investment (ROI), because so many of today’s hybrids build yield through depth of kernel fill. The second pass protects that later-season starch development.

Make sure to watch the brief video Farm Journal’s Matthew Grassi did with Bauer to hear her recommendations on when to apply fungicide to address tar spot, especially her strategy for when or whether to make that second pass.

For an added bonus, Bauer addresses what occurred in soybean fields this spring with the carbon penalty.

A No-Fungicide Decision Needs A Game Plan
Ferrie says he realizes some growers are struggling to make the call to apply fungicides this season, given corn prices.

If you’re still on the fence, he advises making some pre-season yield estimates based on ear counts to help you calculate where an application would help with ROI and where it might not.

In the process, he says to ask yourself these five questions:

1. How well did your crop pollinate?
2. What’s your ear count per acre versus your population?
3. How significant is your disease pressure?
4. Can you harvest the corn crop early, before it falls apart from disease and standability issues?
5. Are you able to dry the crop, if you have to harvest early?

The answers to those questions can help you start to predict what the end result at harvest is likely to be.

“You may have to reevaluate what your yield goal potential is, because if you gave it up at pollination, a fungicide application is not going to get it back for you,” Ferrie says, noting he had that conversation with a grower last week.

“He planned on spraying twice with a fungicide, and now, due to pollination issues, he’s going to only spray once,” Ferrie notes.

If you opt to not spray a fungicide, Ferrie says you need to consider making your contingency plans for harvest now, and you can tweak them as you get closer to running the combine.

“Evaluating your crop now will help this fall and also help you improve what you do next year,” Ferrie says. “Once you’re on the combine, there’s not much more evaluation you can do on a plant-by-plant basis.”

Flying High and Digging Deep — Precision Ag from the Sky to the Soil

Wed, 09 Jul 2025 20:40:27 GMT

Josiah Garber found tar spot lurking in one of his cornfields the last week of June. The southeast Pennsylvania corn grower says that was a first for his farm.

“I’d never found it in July before, much less the end of June. I think the pressure this year is going to be intense with all the moisture around,” predicts Garber, who’s based in Lancaster County, Pa.

Tar spot commonly overwinters as spores in plant residue. During the subsequent growing season, rain and high humidity can promote spores which can be splashed onto corn plants and then develop into what is often called homegrown tar spot.

Tar spot spores can also become air-borne in a field and blow into new fields.

How significant tar spot infections become in any given season depends on the disease triangle – the interplay between a susceptible host, a pathogen and the environment.

A Two-Pass Program Is In Place

Garber’s plan to address tar spot – along with any other disease pressure that’s present – is to make two fungicide applications 21 days apart. This year, the first one went on the crop with a ground rig just before tassel and the second application will be made right after tassel, which was underway last week.

“This is the first time we went with a fungicide application this early, but I’m glad we did since we found the tar spot,” Garber says.

For the past five-plus years, he has been investing in two fungicide applications annually, with both made post-tassel.

“We found that that pays, and once we saw that it would pay, it just became part of our program,” Garber told David Hula and Randy Dowdy during their latest Breaking Barriers with R&D podcast, available now on Farm Journal TV. This episode offers farmers some serious actionable insights to help improve ROI.

To achieve good coverage with the ground rig, Garber says he applies a fungicide/water tank mix at 20 to 25 gallons per acre.

“We’ve been working really hard on our applications, trying to cover below the ear leaf to get optimum performance,” he says. “That’s our goal.”

Droplet Size Impacts Coverage And Efficacy

The goal of getting fungicide placed in the crop where plants can readily use it is what Matt Crabbe shoots to achieve with aerial applications. He typically uses 2 gallons of water per acre as the carrier, depending on the products being sprayed.

“I hear a lot of times people talking water, water, water, but a lot of water can go to the ground and take the product with it if you’re not careful,” cautions Crabbe, owner of Crabbe Aviation, with locations in North Carolina and Virginia.

“Because you’ve got bigger droplets with the plane, you’re putting out a little more volume, and it’s not going to necessarily stay with the plant like I found it does with the lower volumes,” he tells Dowdy and Hula.

To help ensure product stays on plant leaves, Crabbe usually applies products like foliar fungicides at 3’ to 8’ above the crop canopy, maintaining a consistent speed of between 150 and 160 miles per hour.

“I try to keep the application in that range, because our test results show that sets up the droplets at the right size for optimum coverage,” he says.

Get As-Applied Maps For Your Records

Dowdy asked Crabbe whether he provides customers with as-applied maps for their reference and records, post product applications.

“You know, there’s a lot of people that want to overlay yield maps, and then some people just want to trust but verify the good old Ronald Reagan way,” Dowdy says.

Crabbe says modern technology is making as-applied maps easier to provide to growers than in previous years.

“If you place an order on my website, I can press ‘done’ when I finish spraying a field and the system will give you a look at the as-applied map,” he explains.

Crabbe recommends farmers ask their aerial applicator directly about their mapping system as many now have digital platforms where you can get a password to access your specific maps and view application details immediately after completion.

Hear more about getting the biggest bang out of your fungicide buck from Dowdy and Hula on YouTube at Breaking Barriers With R&D: Flying High and Digging Deep — Precision Ag from the Sky to the Soil and on AgriTalk, with Host Chip Flory:

Your next read: Is 600-Bu.-Per-Acre Corn in the Cards This Year for David Hula, the Reigning World Record Holder?

Ferrie: Corn Growers are on High Alert for Tar Spot

Tue, 08 Jul 2025 20:07:10 GMT

Where there’s smoke, there’s fire – and smoke alarms are starting to go off to alert corn growers to the disease fire that’s already ignited in some parts of the Midwest: tar spot.

Farm Journal Field Agronomist Ken Ferrie is monitoring tar spot reports closely and working with growers to create and implement action plans for their specific fields to address the disease.

“We’re finding tar spot here on the bottom leaves, meaning it’s homegrown tar spot,” says Ferrie, who’s based south of Bloomington, Ill. “Finding tar spot here the last week in June means that the plants were infected already by the second week in June.

“There’s no way to sugarcoat this, guys. Tar spot showing up here in June means we’ll have hell to pay in August,” he adds.

The understanding of how the disease progresses quickly came at a cost to Illinois corn growers in June 2021, Ferrie recalls. Few agronomists or farmers understood the impact of what they were seeing unfold in cornfields.

“We weren’t sure what that meant at the time, but by the end of September, anyone in ‘tar spot alley’ realized just how devastating this disease could be. There were massive amounts of down corn with yield hits ranging from 20- to 60-bu. per acre,” Ferrie says.

“Northern Iowa farmers experienced something similar in 2022,” he adds.

You can listen to Ferrie’s complete Boots In The Field podcast, where he discusses how to effectively address tar spot here:

Here’s a look at where the Crop Protection Network has confirmed tar spot in 2025, so far. See county-level infections at Tar Spot of Corn Map :

(Crop Protection Network)

How Tar Spot Differs From Other Corn Diseases

Ferrie says most leaf diseases in corn are a problem because they destroy the leaf surface and tear up the plant’s solar panels – the leaves that fuel corn’s ability to make food.

“When managing most leaf diseases, we are usually concerned about the leaves above the ear. Those are our money makers,” Ferrie says. “When we start scouting, we’re looking one leaf below the ear leaf, and we also look up, looking for any disease lesion and the halos around it.”

With tar spot, the attack is coming from the bottom of the corn plant. “So that is where you need to look when you’re scouting,” he says.

Another way tar spot differs from most diseases in corn is it’s parasitic.

“When it infects the bottom leaves, it will pull nutrients away from the corn plant. So not only will it tear up the solar panels and damage the leaves, but it’ll rob nutrients,” Ferrie explains. “It’ll siphon nutrients off from the plant.”

Like extreme parasite levels in livestock that go untreated, a tar spot infection can pull corn plants down and kill them prematurely.

The plant essentially cannibalizes itself, contributing to reduced yields and standability issues at harvest.

Have Your Plan Of Attack Ready

Every corn grower needs to have a plan in place ahead of time for how to handle the tar spot issue. Farmers needing help in selecting fungicides can check out efficacy ratings and other information the Crop Protection Network offers here .

Ferrie says his standard recommendation for a fungicide application is to wait for brown silk, if disease pressure is not at threshold.

“You want more backend horsepower for those D hybrids – those hybrids that make a big portion of their yield in kernel fill,” he says. “However, if you’re at threshold, spray the field, don’t wait for brown silk.”

Here is a look at tar spot fungicide application recommendations from the Crop Protection Network:

(Crop Protection Network)

Ferrie shares two treatment scenarios for Illinois growers who are experiencing tar spot now – one for those growers in Scott County (where pollination is finishing up) and the other for Woodford County (where pollination is just starting).

“Our recommendation for the Scott County farmers is to spray as soon as the corn is done pollinating, which would be this week,” he advises.

“Throw a hard punch at these fields, because the tar spot and existing disease pressure is there. Then be ready to come back in 21 days with the second shot of fungicide, if warranted, of a cheaper pass. There’s where we throw the generics in, and that pass is to drive stability in your crop stand, so it’ll stand up.”

There are a couple of additional things guiding this application timing. For one thing, Illinois growers still have 60 days to go to protect grain fill in the crop. Another thing to keep in mind, he says, is that the curative factor of a fungicide only covers infections that have happened in the past 48 hours prior to application.

For those fields in Woodford County, Ferrie is telling farmers to wait for their fields to pollinate before pulling the fungicide trigger, because most fields are not at threshold with other diseases present above the ear leaf.

“Again, set up a plan to spray again in 20 to 30 days, and that’ll be weather and disease progression dependent. If we should have a drought – conditions that would slow the disease progress – we might not spray,” Ferrie says. “But If we get the weather pattern to give us a big crop, we most likely will need to spray.”

Ferrie says he understands, given the financial constraints this year, that many corn growers are struggling to spray a fungicide once much less doing so twice this season.

“For the cautious guys out there who are thinking, ‘it ain’t gonna happen, Ferrie; I am not spraying in a $4 corn market,’ this too is a plan. But you need to prepare to go early with your harvest, pre-book some dryer gas and look for pick-up reels,” he advises.

“The good news is we’re ahead of this, and we have experience to fall back on. We have time to react as this does or doesn’t unfold.”

Consider Getting Your Fungicide Applications Booked

Because fungicides need to penetrate the crop canopy and go lower on the plants to address tar spot, that can require adjusting how applicators spray the product.

“If you’re going by air, we need to narrow up the swath,” Ferrie says. “Bigger droplets being applied are the ones that penetrate that canopy, and this goes for planes, helicopters and drones.

“Be aware that when you ask an applicator to cut his swath width by a third, it will come at an increased cost, so be prepared for that. But this step will reduce the streaking issues we often see when spraying tar spot from the air.”

For ground applications to address tar spot, the thing to do is have conversations with your supplier now – plan ahead – as ground rigs cannot cover the same number of acres an aerial applicator can get across in a day. And note, your suppliers probably already had a full lineup of fields to spray before tar spot showed up.

“Remembering back to 2021, growers were waiting two weeks or more to get an application made. If 2025 is a repeat of 2021, we’ll need to go at this from multiple directions,” Ferrie says. “At the end of the day, we need to prepare and scout, scout, scout.”

Sign Up For Farm Journal Corn & Soybean College

Ferrie and his agronomic team at Crop-Tech Consulting are finalizing plans for the annual Farm Journal Corn & Soybean College, as well as the Crop-Tech events.

“These events been approved for 13 CEU credits across four different categories,” he says. “If you need some CEUs, this is a great place to get them.”

The theme for this year’s event is Making A Stand. Topics Ferrie and team are addressing during the two-day program, July 22-23, include:

planter add-ons that pay off
spray nozzle science
in-field planter diagnostics
ear count and rooting depth
bean stress and variety response
integrating soybeans for yield

You can sign up online here or call the Crop-Tech Consulting office to register at (646) 801-0591

Your next read: If You Have an Uneven Corn Crop Pollinating, Consider These 3 Next Steps

How to Track the Potential for Your Corn Crop to Develop Tar Spot

Fri, 13 Jun 2025 19:15:50 GMT

Whether tar spot is a significant problem for corn growers this season is yet to be seen, but one thing you need to know – it’s already showing up in some Midwest fields. The second week of June, the Crop Protection Network (CPN) reported the disease had been found in two states: In the northeast corner of Kansas, Doniphan County, and in the northwest corner of Indiana, Porter County.

Both confirmations of tar spot were on June 11 in Indiana and Kansas.

(Crop Protection Network)

What Conditions Favor Tar Spot Development?

Corn crops with extended periods of leaf wetness are most often impacted by the disease, and that moisture doesn’t have to result from rainfall. Fog, dew and high relative humidity can contribute to the problem as well, according to Bryant Luers, LG Seeds field agronomist.

Shawn Conley, soybean Extension specialist at the University of Wisconsin-Madison, adds that intermittent wet/dry cycles are also problematic.

“Specifically, leaf wetness at night,” says Conley in an online article, What Should I do About Tar Spot?

Purdue University reports tar spot pressure in corn is fueled by:
• Cool conditions (60-70 degrees F)
• Humid conditions (>75% relative humidity)
• Prolonged leaf wetness (>7 hours)

Track Your Potential For Tar Spot

Missy Bauer says tracking weather data, particularly daily humidity levels, is a big part of how she is keeping an eye on the disease this season. She offers some recommendations in the brief, 2-minute video (done in July 2024) on how to use humidity charts like the one she shows here to track the potential for your corn crop to develop tar spot this season.

This is a humidity chart that Missy Bauer developed from weather data in her area during a three-year period. Be sure to watch her video on how to track this information so you can get a good idea of whether tar spot is likely to show up in your area this season.

(B&M Crop Consulting)

“Universities have found when average daily humidity is above 75%, corn crops are at risk,” says Bauer, Farm Journal Field Agronomist and owner of B&M Crop Consulting, Coldwater, Mich.

She wants to get the word out to corn growers that evaluating weather information now – especially average daily humidity levels – helps you prepare for tar spot and put together your fungicide application plan.

You can find the average daily humidity information for your specific area online via Weather Underground and other weather station resources.

Charting Humidity Levels Is Easy

To use the information, Bauer recommends setting two benchmark years, using 2021 and 2022 weather data. The reason for that: 2021 was a high-pressure year for tar spot in much of the U.S. corn growing area, whereas 2022 was a low-pressure year. Learn more in the video Bauer did to explain the process.

She gives you an idea of how to set up the information for tracking purposes. The chart shows you the weather data she tracked from June 1 through July 22 over a four-year period – 2021 through 2024.

Growers should begin scouting for tar spot in corn between V8 and V10, though the disease most often shows up between corn silking and R6.

What to look for: black lesions appear on the top and bottom of corn leaves. With time, these are surrounded by brownish areas of dead tissue that spread from the initial spot. And unlike some other diseases, the spots can’t be rubbed off with a finger.

Conley adds that apps can help farmers in the tracking process. For example, the Tarspotter App can help you determine if the weather has been conducive to put your corn crop at high risk of tar spot development.

Have Your Fungicide Application Plan In Place

Conley advises farmers to have tools in place ready to deal with tar spot. “It’s here to stay and we need to simply be prepared and ready to fight the disease,” he says.

Several fungicides work to help control tar spot in corn. The fungicide efficacy chart available through the Crop Protection Network (CPN) can be used to select fungicides based on the level of tar spot in the field.

CPN adds fungicide efficacy relies on optimal timing. Using fungicides with multiple modes of actions usually results in better control, and in most years, one well-timed (VT-R3 growth stages) fungicide will be sufficient to manage tar spot. In severe cases, a second application may be warranted.

Luers adds farmers will benefit from being proactive in their scouting practices for tar spot, and adjust application timing as the situation warrants. He usually recommends an application at full tassel in fields where tar spot is showing up.

“We need to keep in mind that by the time you start to see visual lesions of tar spot on your plants, the infection has already been there for 10 to 14 days. If you’re starting to see tar spot, your damage is happening as we speak,” Luers says. “If you’re starting to see that before tassel, you probably want to consider moving up your fungicide application timing.”

Your Next Read: 3 Tips To Keep Corn Growing Strong Mid-Season

Triple-Action Foliar Fungicide Targets Tar Spot, Southern Rust and Frogeye Leaf Spot

Thu, 05 Jun 2025 19:38:35 GMT

Farmers will have a new foliar fungicide, Corteva Forcivo, to include in their disease management plans for the 2026 season, pending registration from the U.S. Environmental Protection Agency (EPA).

Forcivo will feature three modes of action – flutriafol, azoxystrobin and fluindapyr – to address foliar diseases in corn and soybeans via overlapping preventive and curative activity.

Key diseases targeted include tar spot, southern rust and frogeye leaf spot, among others, according to Mike Eiberger, U.S. marketing leader for Corteva.

The fungicide will offer farmers these key benefits:

Triple-action foliar disease control. Forcivo fungicide will be available in a convenient premix that growers can apply at a use rate of 7 to 9 fluid ounces per acre. The multiple modes of action will help ensure that if a disease is less controlled by one key ingredient, others will help manage the threat, notes Eiberger in a press release.

Multiple row crop disease flexibility. In addition to addressing disease issues in corn and soybeans, Forcivo will provide broad-spectrum disease control in wheat, barley, sorghum and triticale.

Bolster plant health and yield potential. Forcivo will provide up to 30 days of residual activity to protect crops and maximize return on investment all the way through harvest – even from late-season, yield-robbing diseases – according to Eiberger.

Corteva reports farmers will be able to take advantage of the upfront savings with its TruChoiceoffer and save on their purchase of Forcivofungicide by bundling it with other Corteva crop protection and seed products, such as herbicides, nitrogen stabilizers and Pioneer brand seed. With the TruChoice offer, farmers will be able to save money when funding a prepay account online or through a participating retailer, according to the press release.

Pending registration approvals, Forcivo fungicide will be available for growers to include in their 2026 disease management plans. To learn more about Forcivo fungicide, visit Corteva.us/Forcivo or contact a local Corteva representative.

Your next read: Ferrie: Unravel The Mystery Of Ugly Corn Syndrome To Reduce Yield Losses

Aerial Application Field Trial: Fungicide Protected 20 bu. of Corn Yield

Tue, 03 Jun 2025 18:14:54 GMT

In 2024, a Wisconsin corn grower found a tar spot infestation in his corn field and called Dairyland Aviation to make a fungicide application. The timing was tricky — already late August — and the applicator was skeptical the application would work nearly two weeks after the R4 growth stage. The farmer and the applicator agreed to roll the dice and make the application with a control strip to analyze its effectiveness.

Between the treated field and the untreated strip there were 15 bu. to 20 bu. more.
Despite being outside the optimum window for disease control, this field trial yielded strong results.

From an aerial view, there was a clear line between the treated and untreated parts of the field. Within the canopy, the treated rows were clearly delineated from the untreated.

(Dairyland Aviation)

Since 2018 when tar spot was identified as a widespread epidemic in the Midwest, many crop protection companies, applicators and farmers have explored different ways to protect corn yields from the disease. Tar spot infestations are heavily weather dependent, and the disease thrives in cool temperatures between 60 F and 70 F, with high humidity.

The disease has been either confirmed or reported in Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Dakota, Virginia and Wisconsin.

The National Agricultural Aviation Association details how the above case study used an 800-gal. turbine-powered airplane, guided by a state-of-the-art GPS, at an application rate of 2 gal. of spray per acre. The aircraft’s spray boom used a pulse width modulation nozzle control system — similar to those equipped on ground sprayers.

You can find an aerial applicator near you via the National Agricultural Aviation.

Timely Fungicide Use Safeguards Corn Yield Potential

Fri, 18 Apr 2025 14:50:18 GMT

Applying a foliar fungicide in corn is a go-to practice every year for Chad Eitmann, who grows corn and soybeans in southwest Iowa, near Treynor.

“It wasn’t that way 15 years or so ago, but it is now,” says Eitmann, who says he takes a proactive approach to foliar fungicide use, applying product before he can see any disease show up in the crop.

“The scout and spray method just doesn’t seem to work as well,” he says. “By the time you see any disease, there’s so much that already happened in the plant that you’re over the curve.”

Eitmann says he is particularly concerned about tar spot this year, as the disease is moving into his area. Here’s a look at where tar spot and southern rust were confirmed in the U.S. during the 2024 season. The northern reach of the latter was particularly surprising to the plant science community last year.

Tar spot is on the move in the U.S. The map shows confirmed locations for the disease during the 2024 growing season.

(ipmPIPE)

Southern rust surprised a lot of agronomists and farmers by how far it spread in the northern Midwest during 2024.

(ipm PIPE)

Eitmann says he saw corn crops in his area last year that weren’t treated soon enough for tar spot, and the yield outcomes were affected significantly.

“Some guys [held off] using a fungicide because of the commodity prices and emotion. They were like, ‘No, we’re not going to spend any more money.’ It looked to me like that decision cost them 40 to 50 bushels an acre – maybe more,” Eitmann recalls.

Address Environmental Stressors
Kim Tutor, a technical marketing manager with BASF, says using a preventive application of a premium quality fungicide helps with environmental stress mitigation and optimizes growth efficiency.

A proactive application keeps stomatal conductance working efficiently in corn plants. Essentially, stomates function like small vents on the leaf surface of corn plants, helping with respiration and photosynthesis.

Along with stress reduction, a foliar fungicide application can address diseases in the latent stage of development in the plant — that period between initial infection and reproduction.

Essentially, you can’t see the disease yet with the naked eye, but it is present, invading crop tissue and producing toxins that wreak havoc inside the plant, decreasing productivity and, ultimately, yield outcomes.

Every Disease Is Different
Tutor says a latent period exists for all diseases in corn and soybean crops. Some of the latent periods for economically concerning diseases include:

• Frogeye leaf spot – 7 to 10 days

• Target spot – 8 days

• Southern rust – 7 to 10 days

• Tar spot – 14 to 20 days

The increased risk from tar spot has Eitmann trying to decide how to time his foliar applications this season to get the most residual control possible.

University of Nebraska Extension says most FRAC Group 11 QoI (formerly called strobilurins) and FRAC Group 7 SDHI fungicides are expected to provide between 21 and 28 days of protection of leaves from infection by some fungi.

“Group 3 triazoles can provide some systemic or locally systemic curative activity, but only for infections that have just occurred in recent hours or couple of days,” Extension reports. “Thus, fungicides applied a day or more after infection will not stop all lesion development and some disease development may still be observed.”

Tutor encourages growers to think through their fungicide application timing in order to maximize results for as long as possible. Here is the strategy she recommends, which includes three options, specific to BASF products:

Option 1
BASF commonly recommends farmers use a planned, preventive application of a fungicide with multiple active ingredients and a long residual – at least once per season – to protect corn and soybeans from disease before its presence can be seen on the plants.

“Generally speaking, if I take all the data I have access to and summarize it, the sweet spot for fungicide applications in corn is going to be right around VT R1,” Tutor says. “That’s going to give you the best bang for your buck in terms of a return on your investment with one application.” Tutor recommends a 7 oz. per acre application rate of Veltyma.

Option 2
For growers who have the tar spot inoculum in fields or know it’s in nearby fields, Tutor advises going with a higher product rate rather than assuming two fungicide applications are needed.

“We’re going to recommend you optimize that rate and you take Veltyma up to 10 oz. per acre, again at the VT R1 timing. “Those additional 3 oz. are going to provide a good bit more residual control, and that has the potential to carry you through the rest of the season,” she adds.

Option 3
In those areas where farmers expect heavy disease pressure this season, Tutor does advise going with a two-pass program.

“With that first application, we’re going to recommend you put your best foot forward and go out with the 7 oz. rate of Veltyma at that tassel timing. Then, follow it up a couple of weeks later at the R3 timing, again with a 7 oz. rate of Veltyma or another good product like Headline Amp at 10 or 14.4 oz. per acre.”

Evaluate Results To Determine ROI
Mike Pellett, a farmer near Atlantic, Iowa, says he routinely makes at least one foliar fungicide application in corn, as the payoff has been consistent across acres for multiple years.

“We’re big data people, and the proof is in the results that come off the field,” Pellet says. “We’ve got years and years of data that show a benefit, some years more than others, but as a whole, we definitely know it’s a better decision to spray than to not spray, and sometimes by a big amount.”

Pellett, Eitmann and Tutor discussed fungicide use as part of the BASF media program at the 2025 Commodity Classic.

Your next read: Soybean Farmer Fine-Tunes Seeding Rates For Higher Profits

New Research Finds Hope for Battling Tar Spot

Fri, 27 Sep 2024 14:36:55 GMT

First spotted in Illinois and Indiana in 2015, tar spot has been effecting corn in several states across the eastern U.S. While mild cases can be combatted with fungicides or certain hybrid varieties, more serious outbreaks can result in heavy losses.

But growers fighting an ongoing battle with the disease may see a light at the end of the tunnel with new research from the Agricultural Research Service (ARS) .

The research identified several different species of fungi and bacteria that can stop tar spot from developing.

How it Works
According to Purdue University , tar spot is a fungus, known as Phyllachora maydis, that presents itself on corn plants as small, raised black spots called stromata.

The fungi and bacteria found by ARS scientists grow and reproduce on or inside the tar spot stromata, parasitizing the tar spot fungus and causing failure to germinate.

Researchers used DNA to identify the species and found they are known biological control agents of diseases affecting other crops.

ARS trials found:

Exposure to spores of Gliocladium catenulatum (a commercially available biocontrol fungus) prevented 88% of the tar spot fungus’ stromata from germinating.
An Alternaria fungus isolated from a tar spot stroma prevented about 45% of stromata from germinating.

“Several research studies have demonstrated that some strains of Alternaria alternataare effective biocontrol organisms can reduce the damage caused by plant pathogens,” said Eric Johnson, ARS research molecular biologist, in an agency release. “It may be useful in killing overwintering tar spot stromata given that the tested strain grew well at cold temperatures.”

Moving Forward
ARS reports its studies are still in the early stages and additional research will be necessary.

They are also exploring additional approaches to controlling tar spot, such as:

Examining the basic biology and genetic underpinnings of the tar spot fungus.
Developing molecular markers to speed the search for new sources of tar spot resistance in corn.
Exploring strategies to make better use of fungicides registered for use against tar spot in corn.

Ugh. Tar Spot Moves In After Drought Leaves

High Humidity a Contributing Factor in Tar Spot Outbreaks

Split, Pinch And Push Stalks If Tar Spot Strikes Now

Risk–Reward: Tar Spot Tolerant Versus Susceptible Hybrids

Ferrie: Is Your Corn Crop Running Out of Nitrogen? Why That Matters Now

Tue, 03 Sep 2024 21:12:14 GMT

This week in the Boots In The Field podcast, Ken Ferrie addresses a variety of agronomic issues impacting late-season corn and soybeans across parts of the Midwest.

Here are three of his key takeaways:

1. Nitrogen deficiency is showing up in corn fields, and is extreme in some areas. In many cases, the N deficiencies are enough that Ferrie is able to see them from the road, as plants have yellowed all the way up to the tassels. He recommends checking fields to consider what an insufficient amount of N at this point in the season will mean to yield results.

“Plants running out of N at R4 run the risk of tip abortion,” he notes, as a for instance. “At R5, tip kernels are going to get light, and if it’s a D hybrid, it’s going to cost you in late fill.”

Reflecting on the two nitrogen-friendly years of 2022 and 2023, Ferrie notes that 2024 nitrate samples indicated farmers had lost some nitrogen and needed to replace it.

On top of that, many growers also bumped up yield goals this season, which given yield projections for this fall, that looks like it was a good decision.

“We can see now that bumping those N rates was the right thing to do,” says Ferrie, Farm Journal Field Agronomist. “The more N you had on last fall or early this spring (some of which was lost), the more we had to bump those rates.”

In some cases where farmers bumped up their N applications, they could have been pushed even higher.

“Going through R5, we could see some of these big ears wanting to tip early due to the weight of the ear and long ear shanks. The heat this week will make this even more visible,” he says.

If temperatures drop and some rain comes through for farmers, many of those affected ears will straighten back up. But if the ears tip over due to weight before black layer occurs, that will affect kernel fill and final yield results.

“Many fields have top kill in the corn plants, and it is more evident with stress,” Ferrie says. “The later it shows up, the less damage it’ll do to yield. But if we lose those top three leaves too early, it’ll lighten up the kernels on the top one-third of the ear.

“If you’re running out of nitrogen, you will become a victim of top kill,” he contends. “If you’re deep into R5, the effect will be a lot lighter on you.”

2. More variation is showing up in soybeans: Across parts of Illinois, Ferrie says he is seeing more sudden death syndrome (SDS) along with dry weather stress. The combination is impacting soybeans now in the reproductive stages and is speeding up their maturity.

“We’re seeing the early-planted beans in the drier areas showing some stress and starting to actually change color,” says Ferrie, adding that some of the stress is compaction related and some is a pH issue.

“In some of the higher pH pockets, how far along the soybeans are will play a big role in how much the stress affects the yield,” he says.

3. Pest problems and some disease issues need immediate attention:

Stink bugs: Ferrie says to be on the outlook for stink bug populations. He says to be vigilant in checking soybean seed acres.

Impacted seeds may be smaller, shriveled, and/or discolored, he notes. Damaged seeds may also produce stunted seedlings.

Tar spot: More corn growers are seeing tar spot popping up in their crop.

“Most corn I’ve been in looks like it’s going to make it the black layer, but the plants may be trashed by that time,” Ferrie says.

“Other areas seem to be somewhat clean of tar spot. I do expect that to continue to change as we’re finding tar spot in the upper portions of the plant, indicating that it’s on the move,” he adds.

Southern rust: The disease is becoming more of a problem in the Midwest this year. Temperatures that reach 80°F-plus during the day in combination with warm nights and high humidity will kick up the amount growers will see in affected crops.

Efficacy ratings for corn fungicide management of southern rust have been compiled by a working group of corn researchers and can be found here: Fungicide Efficacy for Control of Corn Foliar Diseases

You can listen to the Boots In The Field podcast for this week here: Episode 341: Boots In The Field Report

Your Next Read: First Generation Farmer Shares How He Found His Way To Success

Ferrie: Corn Is Going Into The Home Stretch, Do You Need To Make A Second Fungicide Application?

Tue, 20 Aug 2024 19:17:47 GMT

Ken Ferrie is hearing from farmers across the Midwest who are trying to decide whether to make a second fungicide application to hybrids affected by heavy disease pressure. In southern Indiana, he is seeing many fields of corn at R5 that are fighting tar spot, which is particularly concerning because of how quickly the disease can take down a corn crop.

“There, many fields have been sprayed twice, and farmers are entertaining a third application,” says Ferrie, Farm Journal Field Agronomist, based in Heyworth, Ill.

At this point in the season, Ferrie recommends corn growers scout fields with tar spot to identify where it is located on the plants. Look to see if the disease is moving around and can be found higher in the plants, and not just along the base of the stalks.

“With corn prices expected to lead with a three in the front, it does make it hard for growers to decide what to do next,” Ferrie acknowledges. “We have corn stretched out here in Illinois from R3.5 to R5, and at R5 we still have 30 days to go in this growing season.”

Another consideration farmers need to think through is how long they will need tar spot infected corn to stand in the field before harvesting it.

“Many of you guys have indicated you’re going to let corn dry in the field, and you don’t care if that takes until December,” he says. “In corn with tar spot in the midway up in the plants at R4 and with the plan to dry corn in the field, you may need to help that crop out with a second fungicide pass.”

Don’t Over-Estimate Yield Counts

2024 will go down as the year of the aphid for many growers. Some hybrids are giving up 15 to 35 bushels per acre to the pest, which is adding insult to injury by contributing to green snap.

“In some fields, aphids have caused the plants to abort one-third to all of the ear. Green snap below the ear means a complete loss, and green snap above the ears is resulting in about a third of an ear, which is probably going to go through the stripper plates,” Ferrie says.

As you do yield checks in these fields, he says to start with all the non-affected corn ears and calculate the yield on them first. Then, make a yield estimate on the poor ears, divide this number by 90, and then add that number to your unaffected ear yield estimate to arrive at your final yield estimate.

“These aphid-affected plants often have uniform stalk diameters, which can be missed when you’re checking your ear counts out there,” Ferrie cautions. “Growers who disregard poor ears and calculate the yield on good ears and use uniform plants as their ear count are going to over-estimate yields.”

Ferrie notes that the impact of aphids is worse on some hybrids than on others, but to not simply resort to pulling those hybrids out of your lineup for 2025, because many of them are high-yielding.

“We just need to be aware if aphids are an issue in certain hybrids as we plan for next season,” he says. “For now, those affected hybrids need to be watched for harvest loss this fall. Don’t let them get through the stripper plate, and get as much corn off aborted tips as possible,” he adds.

Listen here for this week’s complete Boots In The Field podcast: https://www.croptechinc.com/bifr-8-19-2024/

Will Tar Spot be a Problem in Your Corn Crop? This one Tool can Help You Know

Thu, 25 Jul 2024 19:20:58 GMT

Farmers who are watching for the development of tar spot in Corn Country are beginning to see some areas starting to light up with the disease.

“It’s in Michigan, a lot in Indiana, Ohio, even into Wisconsin and Iowa, so there’s definitely tar spot pressure starting to happen,” says Missy Bauer, Farm Journal Field Agronomist and owner of B&M Crop Consulting, Coldwater, Mich.

She addressed the issue this week at the 2024 Farm Journal Corn & Soybean College at Heyworth, Ill.

Bauer wants to get the word out to corn growers that evaluating weather information now – especially average daily humidity levels – signal that you need to prepare for tar spot and put your fungicide application plan together.

You can find the average daily humidity information for your specific area online via Weather Underground and other weather station resources.

Charting Humidity Levels Is Easy

To use the information, Bauer recommends setting two benchmark years, using 2021 and 2022 weather data. The reason for that: 2021 was a high-pressure year for tar spot in much of the U.S. corn growing area, whereas 2022 was a low-pressure year. Learn more in the video Bauer did to explain the process.

She gives you an idea of how to set up the information for tracking purposes. The chart shows you the weather data she has tracked from June 1 through July 22 over a four-year period – 2021 through 2024.

Bauer is concerned that 2024 could see some significant problems from tar spot, because of the higher humidity levels she is seeing this season in the Midwest. Tar spot levels this year for her area, south-central Michigan, are higher than they have been for the previous two seasons.

“While it’s not as bad yet as in 2021, we’re tracking on those higher levels this year,” she says. “As you get daily humidity averages that hang at 75% or above, it’s going to increase the chances we’ll end up having tar spot.”

Corn growers will need to track the weather data for their specific area to evaluate what kind of potential risk their crop could face.

For additional reference, corn growers can get an idea of where tar spot is showing up by county via the website ipmpipe.org/tarspot/ This site is maintained by a combination of university Extension and agriculture industry members.

“Corn growers need to be alert and on-guard, and start scouting for tar spot,” Bauer says. “Make your decisions on fungicide timings and what you’re going to do to treat, and have all your plans in place. The weather data is certainly telling us to be ready for tar spot.”

For additional insights on tar spot:
Tar Spot Disease Pressure Is In the Forecast Now
You Can’t Afford to Be Complacent About Tar Spot
How to Time Fungicide Applications To Best Tackle Tar Spot

If You Have an Uneven Corn Crop Pollinating, Consider These 3 Next Steps

Mon, 15 Jul 2024 21:15:21 GMT

In many areas of the Corn Belt, the crop quality ratings are above average and better. But not everyone is experiencing that type of crop quality this season, especially those growers dealing with extreme amounts of rain.

Ken Ferrie, Farm Journal Field Agronomist, references corn growers in southern Minnesota who have dealt with 17 inches-plus of rainfall recently. Some growers in northern Iowa, parts of Wisconsin and in those areas where rivers have flooded over their banks are struggling as well.

“I can hear it in your voices on the phone, and I see it in your emails – the frustration, the anxiety that you’re going through,” Ferrie says in his latest Boots In The Field podcast.

“Some of you are starting to talk about throwing in the towel on this crop. I can tell you from many years of experience in this business, we never walk away from a growing crop. Hang in there and fight the battle; it will be worth it,” he encourages.

Want more agronomic insights? Consider attending the Farm Journal Corn & Soybean College, which is fast approaching next week. Learn more here: 2024 Farm Journal Corn and Soybean College: Learn How to Ride the Waves of Farming’s Economic Cycles

Extremely Uneven Crop Growth

Ferrie says growers in heavy moisture areas are seeing a lot of yellowing, short or stunted corn as well as a crop that’s very uneven.

“With near-saturated soils, the short, yellow corn of a different height but in the same growth stage and similar number of collars has a much higher possibility of putting on ears and producing grain,” he says.

“However, when we have V7 corn a foot taller than V4 corn, the short corn will not put on an ear. What I’m saying is this corn is under stress and some yield has been lost. But it still has potential to come back from this stress.”

As proof, he references central Illinois farmers’ similar setbacks last year, in 2023, when extreme heat stress practically fried the corn crop.

“Many growers here were ready to throw in the towel last year as June burned up our crop. But we saw a tremendous rebound in that crop,” he recalls. “That was true even in the fields where cover crop issues locked that corn up for weeks.”

Three Next-Step Considerations As Corn Pollinates

A lot of corn is going into pollination this week, and Ferrie says growers can expect their green corn over tile to tassel first, with yellowing corn to be about five to 10 days behind. As a result of the uneven growth and pollination, several things concern him that he wants farmers to consider.

1. The first issue to address could be silk clippers. “This is a problem when it comes to silk clippers like rootworm beetle and Japanese beetle, because they’re feeding on fresh pollen,” Ferrie says. “They’ll travel the plants that have fresh pollen, meaning a small number of beetles can be a problem because they keep moving to the next plant as it drops pollen. We need all this corn to pollinate, we need it to produce as long of ears as we can get.”

He recommends evaluating potential for an ROI from spraying silk clippers. Consult with your retailer or crop protection representative for additional direction.

2. Tar spot is beginning to show up, so be aware of what’s happening in your field. The second issue that concerns Ferrie is the potential farmers in the water-saturated areas will possibly have with tar spot, which can decimate a crop quickly.

“You may be forced to spray early for the tar spot if infestation starts at the bottom of the plant,” he says. “But you may be able to get the first round of tar spot and the beetles in one shot.”

3. Consider doing some nitrate testing. “Some, maybe most of this yellow corn is yellow because of a lack of oxygen,” Ferrie says. “This tends to be worse in corn-on-corn because the microbes use up a lot of oxygen, decomposing last year’s stocks. I suspect when it dries out and oxygen returns, this yellow will go away.”

Be aware, he says, that adding nitrogen to yellow corn deprived of oxygen will not turn the crop green.

“Once it dries up, my recommendation is to pull some nitrate tests and check for both nitrates and ammonium. Check it over the tile lines and compare it to where the short yellow corn was,” he advises. “If we lose too much, we will need to come back with some more nitrogen –30 to 40 pounds per acre – either with high-clearance equipment or airplanes.”

The goal is to feed that crop so it doesn’t run out of nitrogen going into August. Being proactive to feed the crop can payoff.

“After 15.6 inches of rain fell here in June of 2015, we saw a 60-bushel response to our airplanes when we applied rescue N here in central Illinois,” Ferrie recalls.

For growers who have an issue with tar spot, Ferrie offers some additional direction.

“Depending on the rain and the humidity, you may need a second shot of a fungicide for tar spot. We would suggest coming out of the gate with that first spray using a fungicide with multiple modes of action, a longer-lasting product. Then, come back that second time with probably a generic to help you finish out the season.”

Consider Hybrid Types

The type of hybrids planted will make a significant difference in what kind of performance growers can anticipate, moving forward after pollination. Ferrie adds.

“The hybrids that we call a G or L1 – that flex ear size early – have no doubt given up some potential, but they will gain some back in kernel depth,” he says.

“The hybrids that gain a lot of yield in late-season through length and especially depth of kernel, what we call the L2 or D hybrids, it is still game on for these hybrids. The good news is most of the hybrids being planted up there (in those areas hit by extreme moisture) are D hybrids. Stay in the fight,” he encourages.

In other news:
2024 Farm Journal Corn and Soybean College: Learn How to Ride the Waves of Farming’s Economic Cycles

Tar Spot Disease Pressure Is In the Forecast Now

What You Need to Know About USDA’s Surprisingly Friendly Changes to Corn, And Why Prices Seem Unimpressed

University of Nebraska Professor Leads RNAi Research Targeting Western Corn Rootworm

Tar Spot Disease Pressure Is In the Forecast Now

Tue, 09 Jul 2024 19:56:06 GMT

As farm country heads into pollination season, weather conditions have Ken Ferrie concerned about tar spot erupting into a significant yield robber this season. He says he is fielding a lot of grower calls from across the Midwest on the topic.

“Farmers are asking, ‘Is it here, should we spray, when should we spray?’” Ferrie says. “My response is, ‘Do you see tar spot in your fields.’ Finding it is where you need to start.”

As you scout and think you’ve found the disease, an easy way to confirm what you’re dealing with is to take your hand and try to wipe the tar spots off the corn plants (gloves are recommended). If it’s truly tar spot, it won’t wipe off the plants. If you can remove the spots, you’re likely dealing with insect poo.

Ferrie predicts that many farmers in the geography his business covers will encounter tar spot to varying degrees this season. That concern is extended to farmers in northern Iowa, southern Minnesota and central Wisconsin – areas where he says the rains just keep coming.

“Locally (central Illinois), the low humidity in June I think has suppressed the tar spot, but I do expect later infections if this moisture and humidity continue,” says Ferrie, Farm Journal Field Agronomist.

The more difficult prediction for Ferrie at this point in the growing season is how much damage tar spot will wreak in crops.

“Our biggest threat is from what we call homegrown tar spot. The infection comes from within our fields, triggered by the presence of the disease still there,” he says.

“Homegrown tar spot will be more prevalent in your corn-on-corn and in no-till and strip-till fields that still have corn residue from previous crops in them. Everyone under irrigation needs to be on top of this issue, due to the higher humidity,” he adds.

Because very few corn hybrids offer resistance to tar spot, Ferrie advises growers to check all their hybrids for presence of the disease.

“Homegrown tar spot will be the easiest to find below the ear right now. Later, when the disease is windblown around like a morning fog, you’ll find it high on the corn plant,” he says.

Identify Your Group

This season, given commodity prices and the range in crop quality, Ferrie is hearing a variety of different perspectives from farmers on how they plan to deal with tar spot. Farmers are fitting primarily into one of the following four groups.

Group 1 is not going to scout or spray a fungicide at all, because the growers believe products are too expensive and corn is too cheap. This group has probably not lived through the wrath of tar spot yet, in Ferrie’s opinion.

Group 2 is not going to scout, but the farmers plan to make a one-pass fungicide application.

Group 3 will scout fields and pull the fungicide application trigger if needed, based on disease pressure in their fields, pressure in surrounding fields, weather patterns and hybrid type.

“This group is mainly spraying what we call D hybrids, those hybrids that count on depth of kernel fill to get their yield punch,” Ferrie explains. “This group will spray twice if need be.”

Group 4 farmers are not going to scout but plan to spray twice for tar spot, no matter what or if anything shows up. This group has lived through the wrath of tar spot and doesn’t plan on enduring extreme losses from it again.

“They have learned in the school of hard knocks that homegrown tar spot that starts at the bottom of corn plants in late June or early July will eat your lunch at the tune of about 60 bushels per acre, along with down corn,” Ferrie says.

Get Aggressive With Tar Spot

Ferrie offers the following specific recommendations for addressing tar spot this season, given that it’s early July.

For farmers in wet areas where tar spot has been confirmed:

If you’re not going to scout the crop but you have one fungicide application planned, spray the corn at tassel.

“If your corn is uneven due to water damage, wait for the later corn to get tasseled or consult with your supplier on fungicides and surfactants to reduce pinched ear syndrome in corn pre-tassel,” Ferrie advises.

For farmers who are scouting and plan to spray, depending on what they find in the field, Ferrie offers several considerations:

If you see homegrown tar spot low on the plant, spray it. If the corn is not tasseled, take precautions to not get pinched ear syndrome.

“I would plan a second fungicide pass around R3, based on scouting. If no tar spot is present, but other diseases like GLS and northern leaf blight are present above the ear, I would also spray pre-tassel,” Ferrie says.

“If no tar spot is present and other diseases are on the leaves below the ear, our plot results would suggest waiting to spray until brown silk – 10 to 15 days or more after tassel, pull the trigger.

“If your plan is to spray for standability and to protect kernel depth, you’re looking for back-end protection from a fungicide,” he adds.

For farmers who don’t plan to scout fields but plan to spray twice, Ferrie recommends pulling the trigger after all the tassels are out and then a second time about 21 days later.

“On that first spray, I would add an insecticide to make sure you don’t have trouble getting the crop pollinated,” he says.

Key Takeaways on Application Practices

Ferrie says farmers and retailers need to drive their fungicide products deep into the canopy during applications to get optimum results.

If you’re going by airplane, helicopter or drone, he encourages narrowing up swath widths to prevent streaking.

“The bigger droplets that penetrate the canopy are under the aircraft, and the finer droplets tend to stay at the top of the plant, at the outer edges. Flying aircraft closer to the canopy doesn’t give us better penetration, as the air that is bouncing off the ground will catch the spray on its upward lift,” Ferrie explains. “You will most likely have to pay your applicator more to narrow up your swaths.”

On the other hand, if there’s no homegrown tar spot present low on the plants, Ferrie advises “sticking with full-width spraying to keep as much of the product as possible at the top of the plant, protecting those money-making leaves.”

Interested in learning more agronomic insights and practical information from Ken Ferrie? Be sure to join us for the annual Farm Journal Corn & Soybean College, fast approaching on July 23-24 in Heyworth, Ill. Here’s the full details.

Be sure to get all of Ferrie’s recommendations on how to deal with tar spot in this week’s Boots In The Field podcast: