Red corn plants may mean developmental stress for crop

September 4, 2018

Welcome to Crop Talk, with Dr. Megan Taylor your local agronomist with Nebraska extension serving Platte, Boone, and Nance counties. This week I thought I would mix it up and do a question and answer section. There have been some red corn plants popping up around the counties. Maybe this is a good sign that the Huskers are going to have a great season or it could mean developmental stress in our corn plants.

Q:I have red leaves and stalks on isolated corn plants. What is going on?

The red to purplish tint in corn late in the season results from an overabundance of photosynthetic sugars in the stalk and leaves. Sugar was produced by photosynthesis, but the plant had no or limited numbers of kernels in which to move the sugar. Essentially, there was a sink-source imbalance in the plant.

Q: What caused the red pigment in the leaves?

The red pigment could be caused by a variety of stress, but it all goes back to the developing kernels and ear. Temperature, water or disease stress during or just before pollination could affect kernel set and the developing ear. During pollination, throughout northeast Nebraska, high temperatures and high humidity occurred during the critical stages of tasseling and silking. All in all, these stresses can affect kernel set negatively (See Dr. Tony Hoegemeyer’s recent CropWatch article on high temperatures and humidity related to pollination: https://cropwatch.unl.edu/how-extended-high-heat-disrupts-corn-pollination-0 ).

Therefore, with few or the lack of developing kernels, the corn plant had no sink to move the sugar to. Sink organs are photosynthetically inactive and source organs are photosynthetically active. In the case of corn, source organs (leaves) assimilate sugars and move them to the sink organs (kernels) to be stored.

Q: Should I be concerned?

Unfortunately, there is no way to treat red corn and typically the pigmentation will persist throughout the season. This red coloring serves as a red flag when it comes to the production of that particular plant indicating that yield will be low or none at all. This is typically an isolated issue on end rows or in small pockets within a field so it may not affected yield greatly.

For more information or to submit a crop question email me at mtaylor42@unl.edu , call me at 402-563-4901 or tweet @CropTalkMegan.

Megan Taylor is a crop educator with the Platte County Nebraska Extension Office.

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