Individual corn plants that have brown lower stalks are invaded with several fungi that can be identified in the dead stalk tissue. Some, such as Diplodia (Stenocarpella) maydis, Gibberella zeae, Colletotrichum graminicola and Fusarium verticilloides, become obvious in the deteriorating stalk tissue and therefore the naming of the stalk rots as Diplodia, Gibberella, Fusarium and Anthracnose. Although these are the most frequent and most easily identified fungi found in those plants with rotted stalks, the underlying cause of the plant death involved more complicated biology of carbohydrates to the root tissue as the plant moves sugars to the grain. If the movement to grain is too great for the supply from the leaves and stored carbs in the stalk tissue, roots suffer without sufficient energy to meet the root metabolism needs. Eventually deteriorating root tissue succumbs to destruction by soil microbes, resulting with the plant wilting. This allow many fungal species to advance into the dying and dead stalk tissue, destroying the structural strength of the stalk.
Beyond naming the dominant fungus present in the dead stalk, it is important to identify the cause of insufficient supply of carbohydrates. Potential causes are shading from other plants, leaf disease destroying leaf tissue, insufficient sunlight, leaf removal from corn borer, or hail damage.
Stalk rot of corn is a problem in some fields somewhere each year. Complexity of environments and genetics makes conclusions of causes very difficult. Predicting whether this year’s performance is likely to reoccur is not easy.
More perspectives on corn stalk rot can be found by using the search on this page in Corn Journal. It is a subject that I (and others) have studied for a long time.
About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.