Impact of Premature Corn Death

Sep 13, 2023

The last couple heat waves combined with continued drought stress has brought on premature corn death. What should be expected as corn grain harvest gets underway? First and foremost expect VARIABILITY of both grain moisture and yield within and between fields. Next plan for variable and possibly low test weight corn. This is especially important in a drought year where a hybrid may have died prematurely.

While we often talk about test weight as a grain quality indicator, we don’t always remember that test weight and grain moisture are inversely related. Checking fields early at a high grain moisture may give a false ‘low test weight’ indication. As grain dries, test weights increase because kernels shrink and become more slight; this allows for more kernels to fit into a bushel.

We can expect lighter corn test weight because grain fill in late August and early September was impacted by high temperatures and extreme drought conditions. Sure there will be areas of Iowa where timely rains may have saved the corn crop but there is a large portion of Iowa impacted by severe to extreme drought. In addition to lower test weights, expect grain yield decreases more the earlier premature death occurs (ranges from 5-10% in late dent up to 20-40% at beginning dent stage).

Tips for harvesting corn that has prematurely died:

Set the combine for variable crop conditions.
Calibrate yield monitors frequently (at least daily or when you change from one hybrid to the next).
Make drying and storage a priority.

Source : iastate.edu

Video: Wisconsin Corn and Soybean Weed Management Updates and Considerations for 2026 and Beyond

Dr. Rodrigo Werle, associate professor and extension weed scientist, UW–Madison, shares the latest updates and future considerations for corn and soybean weed management in Wisconsin. This presentation covers herbicide resistance trends in waterhemp, including newly confirmed cases of HPPD and S-metolachlor resistance, and emphasizes the importance of residual herbicides and strategic tank mixes for consistent control. Rodrigo also introduces upcoming technologies like Vyconic soybeans and new herbicide products, discusses integrated weed management strategies such as planting green with cover crops, and highlights practical recommendations for 2026 and beyond.

At University of Wisconsin–Madison Division of Extension, we are working to integrate accessibility into our web, video, and audio content. If you experience accessibility barriers using our web, audio, or video content or would like to request complete captions, alternative languages, or other alternative formats, please contact us at accessibility@extension.wisc.edu. You will receive a response within 3 business days. There’s no added cost to you for these services.

The University of Wisconsin-Madison Division of Extension provides equal opportunities in employment and programming in compliance with state and federal law.