Indiana farmer Kevin Kalb leans into learning opportunities.
For 20 years, he’s entered high yield corn contests, and he actively uses those contest acres to apply to the rest of his production. In 2025, Kalb won a non-irrigated class for NCGA with 425 bu./acre.
“We’ve been in this high-yield game for a long time,” he says. “One year, we made 30+ trips in our contest field—but we find out a lot of products don’t work—it’s just a sales gimmick.”
Before the 2025 growing season, he says he’s tried more than 30 biological products. And he had all but written off the entire product category.
“It started five years ago. We had people coming up to ask us to try all these new biologicals, and we’d test strips every year, and we’d never see a benefit,” he says.
Unbeknownst to him, that was going to change after he gave the category one last shot.
“Then, NewLeaf called me and they went through what it does, and that did intrigue me. So, we took out a strip down in one of our contest fields with some of the best ground that we’ve got, and lo and behold.”
Lessons Learned, Lessons Applied
Where four out of five years Kalb is used to tackling tar spot a new disease has emerged as a yield robber—southern rust.
In 2016, he had his first run in with southern rust. In the most severe cases across his farm, yield was docked 100 bu.
“That hit us extremely hard. At the time, our program was one aerial application of fungicide, and we thought we were good,” he says. “This year, those farmers in Iowa had their first experience with Southern Rust. And it’s ugly.”
With the influx of southern rust in 2025, the new tool in his toolbox for this past growing season was a sample of NewLeaf’s TS601 biofungicide and Terrasym 450, which he applied in-furrow at the time of planting.
“Around the 4th of July, we really didn’t see much rust yet. But already in the season what we saw from the 601 was great big stalks–probably a quarter the size bigger than what our other ones were,” Kalb says.
That was his first evidence in how his perception of biologicals may be turning around. However, what came next flipped him 180 degrees.
“Then, southern rust came in. Compared to our normal fungicide application protocol, the biofungicide and biostimulant showed a 6 bu. increase,” Kalb says. “But the kicker is, it would have saved us almost $70 an acre. That was eye-opening, the input cost was so much cheaper with that product—it preserved yield and cut inputs.”
Kalb is convinced. So much so he’s planning to put TS601 and Terrasym 450 across all his acres.
“Normally, we test everything 3 years before we move it over into all of our production acres,” he says. “These are the first products that we’ve ever used that we switched to 100% of our acres for next year.”
What Does He Credit The Transformation In His Experience?
“I think everybody should have 10, 20, 30 acres on their farm where they sit there and play with different rates and this and that,” Kalb says. “And you can’t do it just one year. You’ve got to have several years.”
That’s how he’s translated high yield lessons to the rest of his production.
Kalb credits his focus on soil health, specifically soil microbes, that took his yield plateau from 350 bu. to bumping above 425 bu.
“We started cutting back on synthetic fertilizers and building out a low-salt crop fertility program,” he says.
He says his below-ground balance of bacteria and fungi populations may have actually hindered the performance of some previous biologicals he’s tried. But for TS601 and Terrasym 450, which colonizes around the roots and grows as the plant grows, it was a match.
“Like anything else, I think biologicals have had the benefit of improving with time—they’ve come a long way. I see now how they can not only bring yields up, but cut inputs down. The biggest question is the same question there’s been—finding the ones that work,” Kalb says.
