Where does fungicide benefit?

My fungicide trial has been going on now for two years and I have one year to go. I am seeing trends taking place with ROI (return on investment) when talking about the application of fungicides. Selecting the right hybrid is the first part of putting a good defense out in your field, but sometimes the offensive hybrids are hard to walk away from. If that’s the case, then selecting a good fungicide program is a must. Every year it seems there are different hurdles we all have to jump over, whether it is too much rain, hail, drought, insects, or diseases that try to play into our plans. Below is a quick summary of what I have observed so far.

Using Prairie Brand’s 6056 as my test hybrid, I have seen very good response numbers over the past few years. I have applied at V5 to V7, at R1, and at both V6 and R1. There are positive things I have seen with all applications.   So far, the best ROI would just be at R1. The best numbers have come from the application of both growth stages, but if you are not making any kind of pass over your corn at V6, I’m not sure if it pays to do it alone. Comparing the two years together, the trend is still the same. Even with the lack of disease pressure, the added benefit of the fungicide is more than enough to justify the use of it. The dry summer that we had showed some effect on the check in my testing compared to the fungicide applications. The stress that the corn plant takes from these hot and dry seasons can be handled better with the fungicide helping the plant rest by lowering respiration rates at night to help utilize water and nutrients.

I think there is more than just yield benefit when making the right choices for your crops. If we were to have a bad outbreak of foliar diseases this year, I think a fungicide pass pays with yield, plus the standability that it can return this fall when you are making passes with your combine. I will be running this trial one more year. I will compile the three-year data this fall and give a more detailed finding of the fungicide trial. I feel confident that my results will be similar to the past two years.


If you have any questions or want to discuss more on what I am doing with this trial, please reach out to me.


Mark Johnson

Iowa Regional Agronomist