By Scout Nelson
Fungal diseases can greatly reduce corn yields if they are not managed properly. In southern Minnesota, farmers closely watch their fields during mid-to-late summer to protect crops from diseases such as Southern Rust and Tar Spot. These diseases spread through airborne spores and can quickly damage corn plants if weather conditions favor their growth.
Jonathan Eisenthal from Minnesota Corn highlighted that farmers, agronomists, and researchers work together to monitor disease activity and improve fungicide timing. Their efforts help growers protect yields, reduce production costs, and use crop protection products only when they are truly needed.
Tar Spot survives in crop residue and returns each season, while Southern Rust arrives from southern states through strong winds. Farmers often monitor disease reports from neighboring states to prepare for possible outbreaks before infections become serious.
Scouting fields is an important part of disease management. Farmers inspect corn leaves for early signs of fungal spores before infections spread. The biggest challenge is deciding the best time to apply fungicides.
Applying too early may require another treatment later, while applying too late can allow diseases to reduce yields significantly.
Weather also plays a major role. Cool and wet conditions encourage fungal diseases, while extended hot weather often slows their development. Understanding these conditions helps farmers make better treatment decisions.
The Minnesota Corn Research and Promotion Council supports research to improve disease forecasting. Root Applied Sciences has installed spore detection equipment across southern Minnesota to monitor disease pressure.
The company uses technology that previously helped vineyard managers reduce unnecessary fungicide applications by improving disease prediction.
“Are we trying to get more plant health or are we try to make sure the fungicide is on there, as a preventative, before the disease ends up setting in?” explained Brandon Fast.
“The EPA has tested these fungicides for safety for decades. They are very safe to use. You might see a high clearance sprayer or an airplane and it looks like an awful lot of material is being put on the crops. In reality, it’s only a little more than 6 ounces of fungicide per acre, which we mix in with about 20 to 30 gallons of water, for each acre that’s sprayed.”
Farmers also emphasize that fungicides are sprayed on the upper leaves, not directly on developing corn ears protected by their husks.
Photo Credit: gettyimages-fotokostic
Categories: Minnesota, Crops, Corn