While corn harvest is still underway in much of Illinois, Ken Ferrie says he already sees at least three takeaways for farmers in the state, particularly in the central region.
First, he sees an increasingly strong correlation between disease pressure in corn, summer weather patterns (particularly those involving heavy, frequent rains) and poor yield outcomes.
He explains that from June 23 through August 23 fields at his central Illinois office, near Bloomington, received rain 41% of the time (about 25 out of 62 days). Some of those rain events totaled 9” of rain in a brief period of time and included high winds, resulting in corn that goosenecked, sometimes in two different directions.
“This I believe really fueled the disease pressure that we’re dealing with here locally,” says Ferrie, Farm Journal Field Agronomist and owner of Crop-Tech Consulting, Heyworth, Ill. “When you get a few miles outside of the heavy rain and wind events, not only does yield improve, but the tar spot disease pressure lessens and the corn has stayed green longer.”
Second, he is seeing significantly higher corn yields in those areas hardest hit by disease and bad weather when two fungicide applications were made—enough of a yield increase to have made two applications financially worthwhile this year, which is uncommon.
“Double spraying at/or after tasseling looks to be paying some pretty big dividends,” Ferrie says. “We’re also seeing spraying that was done at V10 and at/or after tassel doing pretty well as well.”
He attributes the benefit of two applications to the fact that he and other agronomists first saw tar spot in central Illinois cornfields on June 30, much earlier than what they have seen it in the five or so years the disease has been found in the state.
“I’m blown away by the idea that we thought tar spot was a late August or early September disease (only),” he says.
His third takeaway has to do with farmers’ hybrid selections for 2022. Specifically, Ferrie says to not be overly quick to throw out your lead hybrids based on this year’s yield results. Those hybrids may still have a place in your lineup.
However, he says, “This year does teach us a lesson about the need for hybrid diversification.”
Ferrie and the Crop-Tech agronomic team are in the process of putting together a list of hybrids for next year that they believe will be good options for fields most at risk for another round of tar spot.
Ferrie wants to clear up some confusion growers may have related to how he refers to some hybrids.
“I get used to talking with Crop-Tech customers and using our terms and nomenclature that we have for different things that we’re working on, such as our hybrid yearbook project, where we put labels on the hybrids to identify G, L1, L2 and D hybrids,” he says. “This has to do with how hybrids flex, their ear flex.” Ferrie adds that when he talks about hybrid flex it always refers to a type of loss not a gain.
In summary:
- G hybrids flex down in the number of rows around the ear when they are stressed. Ferrie says this happens early in the growing season.
- L1 hybrids flex down in length, usually cob and all. “So, the ear may be filled to the tip, but it’s only 30 (kernels) long,” he says. “This means that that hybrid flexed down in ear size before tassel.”
- L2 hybrids flex down in ear size after pollination. “So, it may be pollinated to 45 (kernels) or 50 long but it will work back to 30, leaving a shriveled ear tip with kernels on the end of it,” he says.
- D hybrids flex in kernel depth, which limits the amount of starch produced in the kernel.
When corn dies early, like it did in areas of heavy disease pressure this year (and can also happen under severe drought) the L2 and D hybrids tend to be most negatively affected, because they need good weather conditions during the last 30 days of grain fill. Corn dying early forces those hybrids to go to black layer too soon and robs them of kernel depth.
“These hybrids are about 30 bushels per acre off our August estimates because they didn’t get the kernel depth they needed,” Ferrie says. “The disease pressure took it away even though we had some great fill days at the end of August and in the first part of September. Because those plants didn’t stay alive, we couldn’t take advantage of those good days.
“The odds of us having this kind of disease pressure next year, I’m going to guess are probably low,” he adds. “But this year does teach us a lesson on diversification of our hybrid selection to mitigate in-season stressors.”
Ferrie: 4 Timely Harvest Reminders plus Yield Highlights for Illinois Corn and Soybeans
Ferrie: Severe Tar Spot is Shutting Down Corn, Encouraging Top Leaf Dieback
Ferrie: Disease Pressure is Bringing Corn to its Knees
You can hear this week’s podcast here:
