As we move into the first week of June, corn that was planted “early” (March) is likely now tasseling or will be soon. This is a reminder that water demand in corn is at its peak, using 2.1 inches per week. The forecast is favorable for rain across the state over the next two weeks, however, if we do not meet the 2.1″ per week requirement, supplemental irrigation may benefit.
I have gotten several questions about nitrogen application termination. Our recommendation is to terminate nitrogen applications by R1 or when the silks have turned brown on the ears. At this time, approximately 75% of corn’s total nitrogen uptake is complete, and high rates of N this late in the season are not recommended.
The last update would be in response to fungicide applications on corn. We generally see people try to apply fungicides around tassel or silking on corn, so this will be or is already on many producers’ minds. A few things to consider when deciding if you need to apply a fungicide or when to apply a fungicide. First, how risky is the field of corn to developing disease? Was the corn planted early or late (March vs April). If planted later the changes of a disease like southern rust blowing in from the South are greater and could have a more sever impact. To date, no southern rust has been found in SC on corn. Is the corn following corn within rotation (was it corn in 2024?). If so, disease could have overwintered on debris in the field and provide a source that could then spread to this year’s crop. Does the hybrid have good disease resistance, especially to Northern Corn Leaf Blight, Southern Corn Leaf Blight, and Grey Leaf Spot? If the hybrid has unknown resistance or low resistance then a fungicide application may become warranted.
Typically when making fungicide recommendations, scouting for disease is done at or near tassel to determine if there is disease already developing in the field. This year I have already seen fields that were planted corn behind corn and have high levels of Grey Leaf Spot in them pre-tassel! This is not an every field issue but each field should be evaluated before pulling the trigger on fungicide.
The goal for the fungicide application is to keep the leaves, especially the ear leaf, clean through Dent (R5). From silking (R1) to dent (R5) is often 30+ days. If we apply immediately at tassel and no disease has been found, then we are really expecting a lot out of the fungicide to control disease for 30+ days. If you can wait to apply, the chances of the product residual getting the crop to dent are better.
If you have any questions or concerns about fungicide applications, timing, or products, please contact your local agronomy agent.
