Harvest will be here before you know it, which means we are closely monitoring our corn fields for late-season lodging. Stalk rot in corn is an outcome of when the plant can no longer transport water and carbohydrates effectively throughout the stalk. 

Harvest will be here before you know it, which means we are closely monitoring our corn fields for late-season lodging. Stalk rot in corn is an outcome of when the plant can no longer transport water and carbohydrates effectively throughout the stalk. This is caused by both biotic (fungi and bacteria) and abiotic factors (drought and flooding). Stalk rots are common in corn, but the severity can be increased when inoculum is highest in corn-after-corn and reduced tillage acres. Stalk rot inoculum occurs naturally in the soil profile and plant residue for a plethora of pathogens.

Scouting occurs later in the season when signs and symptoms start to appear. The two basic methods used to scout for stalk rots are the "pinch" and "push" tests. The pinch test is done by pinching the lower stalk between the two lowest internodes to see whether the stalk can withstand the pressure. If the stalk caves, it fails the test. For the push test, push the stalk to a 30-degree angle. If the stalk does not spring back up, then it fails the test. If 10% of the tested stalks fail either of these tests, then prioritize that field to be harvested first or cut at a higher moisture and dry grain to prevent late-season lodging.

Management techniques can vary depending on the specific disease present, so correct identification is key.

 Stalk will have black, shiny lesions typically blotchy and disintegrated pith.


Hybrid resistance, reduced plant stress, and crop rotation.

Stalk can have dark brown, water-soaked lesion; soft, slimy tissue; foul odor; twists during lodging. Plant tips can be slimy and rotten and may die prematurely.


 Avoid overhead irrigation using pond or surface water, provide proper drainage, and avoid plant stress, including insect damage.

 Stalks and roots can be covered in black fungal structures. The pith will be disintegrated and covered in black-silver fungal structures.


Hot and dry conditions (soil temperatures > 90 degrees) near physiological maturity.


 Irrigate during dry, hot seasons and avoid common plant stressors.

Stalks will show brown/black fungal structures embedded in the rind, and the pith will disintegrate.


 Crop rotation, hybrid resistance, tillage, and avoiding plant stressors.

Dull green leaves and disintegrated pith with salmon-pink discoloration.


Dry conditions before silking followed by warm, wet conditions after silking (80-100 degrees).


Reducing plant stressors (control foliar diseases, field drainage, avoid high nitrogen, and low potassium soils).

 Small stalk with black fungal structures that can easily scrape off. The pith will disintegrate with pink-red discoloration.


 Avoid wheat/corn rotations and plant stresses and wounds.

 Stalk twists during lodging; leaves are green, even after lodging, and soft, brown, water-soaked pith and rind.


 Avoid overhead irrigation water using pond or other stagnant water, provide proper drainage, and avoid common plant stressors.

Photo Sources:
1. https://cropprotectionnetwork.org/encyclopedia/anthracnose-stalk-rot-of-corn 2. https://plantix.net/en/library/plant-diseases/300035/bacterial-stalk-rot-of-maize/ 3. https://cropwatch.
unl.edu/corn-stalk-rots-2018 4. https://cropprotectionnetwork.org/encyclopedia/diplodia-stalk-rot-of-corn 5. https://cropprotectionnetwork.org/encyclopedia/fusarium-stalk-rot-of-corn
6. https://cropprotectionnetwork.org/encyclopedia/gibberella-crown-rot-and-stalk-rot-of-corn 7. https://cropprotectionnetwork.org/encyclopedia/pythium-stalk-rot-of-corn