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Agronomy Talk


Common Stalk Rots To Watch For

Published on Friday, September 23, 2016

As we near harvest, I wanted to review stalk rots. We commonly see a few of them in Iowa that cause a lot of headaches during harvest.

Anthracnose Stalk Rot begins as narrow, dark lesions on the stalk and can spread, turn shiny, and grow darker as the season progresses. It’s most visible when it causes the top of the corn plant to die back a few short weeks after pollination. Prevalence is higher in continuous corn and fields with reduced tillage.

Diplodia Stalk Rot causes a weakened, shredded pith and can cause plant death. Symptoms are tiny black dots on the internodes. Prevalence is higher in continuous corn.

Fusarium Stalk Rot can be difficult to identify but is common in the Corn Belt. It can cause a weakened, spindly pith that is white or light pink. Unlike Gibberella or Diplodia, it doesn’t produce black specks on the outside of the stalk. Whitened nodes are the only visible symptom.

Gibberella Stalk Rot can be identified by a distinctive pink or red pith near the node. It can also cause premature death. Gibberella may cause black spots like Diplodia, but they can be scraped off.

Hopefully you won’t see these stalk rots in your fields, but if you do, this can help you make better management decisions when harvest rolls around. 

Author: Greg Shepherd