This year on the Hefty Farm, we implemented new testing in what we call…
“THE CRAZY TRIALS.”
One area of research we explored was making post-emerge herbicide applications in corn. You might not think of this as ‘crazy,’ but in the sense of how much money you might be leaving on the table, it could be considered! As weeds become harder to kill with glyphosate and even HPPD chemistries, many farmers are looking at additional herbicide options. For example, dicamba has been on the market since the 1950s, and its use in foliar post-corn applications has typically been considered a last resort; but today, more and more farmers are adding dicamba to their corn post applications.
AS WE BEGIN TO MIX MORE CHEMISTRY IN THE TANK, WHAT EFFECT DOES THAT HAVE ON YOUR CORN YIELD?
THINK ABOUT HOW A CORN PLANT DEVELOPS.
In its early stages, corn begins germination as the radicle breaks the seed coat. Then, the coleoptile pushes to the soil surface, and the first true leaf emerges. The first three leaves of the corn plant are already inside the corn seed when you put it in the ground. From V3 to V6, that plant will determine all of its leaves for the year and begin to expand them out as the growing point moves above the ground at V6. By V5, the plant has already determined how many rows around its ear will be.
THE REASON I BRING ALL THIS UP IS TO ASK THIS QUESTION:
WHEN DO FARMERS TYPICALLY MAKE A HERBICIDE APPLICATION IN CORN?
FROM V2-V6. That means the plant is conducting some of its most critical functions in determining yield for the season all while it’s trying to process and metabolize herbicide.
I’ve referred to the stress following herbicide applications and its effect on yield as the HERBICIDE TAX. When you spray a foliar product like glyphosate on crop, the plant has to decide if that toxin is something it can process and metabolize or if that toxin is going to kill the plant itself. Regardless of trait tolerance, this takes a tremendous amount of energy away from critical functions like foliar leaf development, root development, and even beginning stages of yield determination.
The energy a plant uses to process applied herbicides is a tax it has to pay in order to survive
– THE HERBICIDE TAX.
In previous research articles, we’ve often talked about MegaGro; this year, it’s showing great results once again. In fact, across 13 years of research, we’ve seen an average yield increase of more than 6.5 bushels per acre in corn. However, MegaGro is patented as a glyphosate safener because it functions by overloading the plant with auxins to speed up how the plant metabolizes glyphosate chemistry.
Returning to the 2025 Crazy Trials from this year, we looked at different timings and products that fall into the dicamba category. When comparing applications made at V2 and V8, we saw some pretty striking results. Spraying Clarity herbicide late at V8 rather than on time at V2 resulted in an 11.6-bushel yield reduction! What implications does this mean for growers who make revenge sprays later in the season? We saw similar results in other products. An application of DiFlexx at V8 showed a 7.8-bushel reduction in yield versus spraying at V2. Further, at the V2 timings, we added MegaGro to the tank with Clarity and DiFlexx. In both occasions, we showed higher yields with MegaGro being included in the tank (+7.87 bushels with Clarity and +4.10 bushels with DiFlexx).
WHAT WAS MOST INTERESTING WAS THE COMPARISON BETWEEN V2 CLARITY HERBICIDE, AND V2 DIFLEXX PLUS MEGAGRO:
MORE THAN A 10.16-BUSHEL DIFFERENCE!
DiFlexx has the CSI safener from Bayer, so it’s slightly different from Clarity herbicide. It also runs roughly $11 more an acre than Clarity, while MegaGro is roughly $5 an acre – roughly a total increase in cost of more than $16 an acre. However, keep in mind a yield increase of 10.16 bushels represents an ROI of more than 2.7 using a corn price of $4.25. I think that this presents a compelling argument for running DiFlexx and MegaGro versus just Clarity herbicide in the post pass at V2. This directly relates back to how much the Herbicide Tax costs the plant to process and metabolize these chemistries.
EITHER WAY, IF YOU ARE RUNNING A DICAMBA CHEMISTRY PRODUCT IN WITH YOUR POST APPLICATIONS IN CORN, MEGAGRO SHOULD BE INCLUDED IN THE TANK.
When discussing this in the past, I’ve had farmers point out that dicamba is an auxin, as well as MegaGro. How can one auxin help another in the plant? The auxin class of chemistry in dicamba is an unregulated auxin. Once it’s in the plant, the plant doesn’t know what to do with the active material and it runs rampant within. In a susceptible plant, it moves to the growing point and forces the plant to grow itself to death. On the other hand, MegaGro is an auxin that the plant naturally makes – IBA. When the auxin from MegaGro enters the plant, the plant instantly recognizes it and uses it to make critical decisions to process and metabolize the unregulated auxin found in dicamba.
EVEN THOUGH BOTH OF THESE PRODUCTS ARE AUXIN-BASED, THEY DO TWO COMPLETELY DIFFERENT THINGS INSIDE PLANT TISSUE.
When it comes to the Herbicide Tax, no matter what chemistry you spray, the plant has to spend energy to ensure it stays alive, even if the chemistry itself won’t kill the corn crop. Tools like MegaGro can aid in minimizing this tax, and you can also select products that treat you better in the long run compared to a generic.
AS YOU CONSIDER YOUR DECISIONS FOR THE 2026 CROP, REMEMBER EVERYTHING YOU DO TO THE PLANT CAN HAVE AN EFFECT, BOTH POSITIVE AND NEGATIVE.
How you minimize the negative effects will determine how many bushels you can harvest at the end of the season. As we’ve seen year in and year out for more than a decade, adding products like MegaGro to the tank is an excellent way to minimize that tax.
