Rescue Nitrogen for Corn in Iowa: Is It Too Late in 2025?

Late-season nitrogen rescue applications aren’t always necessary—but this year, many Iowa fields are showing signs that they might be. Between above-average precipitation, early N loss, and delayed sidedress applications, the conditions for in-season N deficiency are widespread. If you see visual signs of deficiency and your crop still has strong potential, a rescue application applied as soon as possible could help recover some yield potential. Ultimately, applying some N is often better than applying none when the crop is short. The longer the deficiency goes uncorrected, the greater the potential yield loss. In a year where so many things are out of your control, rescue N is one tool you still have time to use effectively.

Regional Crop Update: June 30 - July 8, 2025

Tassels started showing in cornfields across the state, while soybean fields are flowering and some are starting to set pods. ISU Extension field agronomists reported a range of concerns and observations over the past week, including potential herbicide failures, low levels of foliar diseases such as gray leaf spot, tar spot, and northern corn leaf blight, rootworm injury, and soybean gall midge being found in two new counties. Below, field agronomists share more details about what they’re seeing in their respective regions.

July soybean insects update