Top kill is a process that happens to varying degrees in the cornfield every season. The question to ask yourself is: How soon does it happen in your fields?
“If it happens at black layer or after it’s no big deal. But if it happens 10 to 15 days before black layer, it’s going to basically take away some of your depth – essentially your kernel depth out there, and you’re not going to have the test weight you want,” explains Ken Ferrie, Farm Journal Field Agronomist and owner of Crop-Tech Consulting Inc., Heyworth, Ill.
There is no fungicide on the market that can prevent or alleviate top kill. But Ferrie says he knows from Farm Journal field test plots that the more stress you can alleviate during the growing season, the longer the crop stays green and adds grain depth and weight and top kill is delayed.
Compare And Contrast
A variety of management practices – or the lack therein – can speed up the top-kill process even more, including compaction, diseases and nutrient factors.
The opposite is true as well. The better your agronomic practices, incorporating the 4Rs, the less top kill your crop will undergo and the better your final yield outcome.
You can see in the first photo of Ken Ferrie a case of the haves and the have nots. On your left, is a hybrid that is undergoing top kill and headed toward black layer prematurely. On the right is the same hybrid, but it has had adequate nutrients and other agronomic benefits throughout the growing season.
In addition, check out the ears Ferrie has pulled to show the difference in size between them. The set of ears in his left hand (to your right) is significantly bigger and heavier.
“As we look at the ears from this set, this is the full-meal deal with the full nutrient load,” Ferrie says, regarding the ears.
“And this is where we backed that nutrient load down, and we have top kill in about 90% to maybe 100% of the plants,” he says of the ears in his right hand (on the left side of the screen). There is a difference in this ear size; I can definitely feel the difference in the weight and how the ears are filling.”
Ferrie and team produced a 3-minute agronomic video to provide you with more insights. You can watch it here:
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