Published on Wednesday, October 31, 2018
Click here for a downloadable version of this Agronomy Talk update
There are numerous stalk rots that affect corn in mid- to late-season. Weather, nutrition and genetic disease tolerance all play major parts in the disease cycle. Plants move nutrients from the stalks to the ears during grain fill. High yields mean heavier ears. These two phenomena combined can make stalk quality issues a problem even in very high-yielding areas.
Disease: Bacterial Stalk Rot
Disease: Charcoal Rot
Disease: Diplodia Stalk Rot
Disease: Fusarium Stalk Rot
Disease: Gibberella Stalk Rot
Disease: Pythium Stalk Rot
Disease: Physoderma Stalk Rot
In general, well-fed plants tend to be healthier and have fewer disease issues. Plants with inadequate soil fertility will cannibalize the stalk, leaving the stalk more prone to infection from stalk rots. Stalk cannibalization can mimic stalk rot disease because symptoms are weakened stalks and lodged corn. Adequate N and K are critical for stalk integrity especially in years with above average rainfall and consequently higher disease pressure. High kernel set triggers the need to pull nutrition from other parts of the plant to fill the kernels. High yield levels can increase stalk cannibalization and lead to higher lodging.
Above: Stalk pinching due to stalk cannibalization without the presence of stalk rot diseases.
Photo by Mike Hannewald
Many common stalk diseases can overwinter on corn residue or other cereal crop residues. Heavy tillage can help to manage disease inoculum.
Work with your trusted Beck’s advisor to scout prior to harvest to get a plan in place for harvest priority. Often the benefits of early harvest and the use of drying systems outweigh the headaches and yield loss of allowing corn to dry in the field and risk stalk rots.
Planning for the Future:
Select hybrids resistant to common stalk rots, keep in mind ratings may not be available for all common stalk rots. Planting a wider range of maturities can also spread out maturity and help to manage risk of infection opportunities for your whole operation. Traited hybrids provide good protection against insect pests and reduce overall stress during the growing season. Many stalk rots can be somewhat opportunistic on fields already compromised by physiological or environmental stressors.
For a video explaining how to evaluate stalk quality in your fields, click here.
Author: Eric Wilson
Categories: Agronomy, Agronomy Talk
Tags: corn, Disease, stalk rot, residue management, corn stalk rot, plant stress