Wheat farmers have asked us for years – “Why aren’t corn farmers using more foliar fungicides?” It’s puzzling to them because foliar fungicides have shown increases in plant health and yield in wheat for so long, they’ve become “no-brainer” applications. The only question in wheat is whether farmers should use all three popular foliar fungicide application timings: at early herbicide spray, flag leaf, and heading. For your corn acres this year, here are a few situations to consider applying a foliar fungicide.

Wet Years

In the wetter years, foliar fungicide use is often at its maximum. Everyone is concerned about the high risk of disease in wet years. This is how fungicides have been thought of forever. They are disease prevention products that need to be applied ahead of or at critical growth stages such as ear leaf, tassel, or kernel fill.

Conclusion: Foliar fungicides are a “no-brainer” on wet years especially IF they can be applied before disease begins.

Dry Years and Hail

Both in drought years and when applying fungicide after hail, we’ve seen plant health benefits, better standability, and nicer-looking plants after spraying. However, this doesn’t always translate to a yield increase. In our area – where we haven’t had any of the “bad” diseases like gray leaf spot, northern corn leaf blight, southern rust, or tar spot – tassel applications haven’t paid in the dry years. However, spraying in the V5 to V8 timing has been okay, mostly because we may already be spraying something else so we aren’t making a separate trip, and also because many people have been using reduced rates at that early timing.

Conclusion: We would probably advise spraying after hail. We would probably not advise spraying during a drought year around tassel time if you aren’t in a heavy disease area, but if you want to spray early to get more of the plant health benefits, that could pay.

Tar Spot

Tar spot may now be the biggest yield-robbing disease of them all. We’ll see how that plays out in the coming years. In 2021, though, this disease robbed a ton of yield from corn farmers, but it doesn’t have to be that way. For your farm, if tar spot has already become a reality, a multiple application approach is the best in-season plan. Start with a tolerant hybrid. If it were me, even though Xyway is not labeled for tar spot control, I’d still use it to keep plant health up and reduce other diseases in the plant. Then, I’d make foliar applications shortly before tassel and follow up again about three weeks after that. A number of fungicides are now labeled for control of tar spot, including Delaro Complete, Lucento, TopGuard EQ, Trivapro, Miravis Neo, Veltyma, Headline AMP, and Revytek.

Conclusion: Multiple applications of foliar fungicides are a “no-brainer” for help with tar spot.