The end of harvest doesn’t necessarily mean the end of corn disease management. Disease-causing pathogens can persist in infected corn residue, making field history and residue conditions useful considerations as you plan for the upcoming season.
Winter is an ideal time to assess which fields may carry greater disease risk and determine whether changes to crop rotation, corn hybrid selection or fungicide planning could improve long-term productivity and resilience.
Start by identifying where corn disease pressure is most likely to be a problem in your fields. Most corn foliar diseases including gray leaf spot, northern corn leaf blight, and tar spot can overwinter in corn residue. On the other hand, some diseases such as southern corn rust will not survive northern winters, but depend on southern winds to blow spores from the southern US and Mexico each season. Although there may be limited overwintering, most common rust infections also depend on southern winds moving spores from the south each year. Most seedling diseases and stalk rots can also over winter over to infect next year’s corn crop.
Assess which acres carry the most disease risk
As you review last season’s field records, consider a few questions when assessing disease risk:
- Which diseases were present?
- Which fields had the greatest disease severity?
- Which hybrids appeared particularly susceptible?
- Which fields have the greatest amount of infected crop residue remaining?
Disease this season doesn’t automatically mean you’ll face a severe outbreak next year. Disease development still depends on factors such as weather conditions, crop susceptibility and the amount of pathogen inoculum present.¹
Field history can therefore help you identify which acres may carry greater risk heading into the next season, rather than predict disease severity with certainty.
Use rotation and corn residue management to lower corn disease pressure
Even if your fields have a low potential risk for disease, appropriate crop rotation and residue management help reduce the buildup of some residue-borne and soilborne pathogens by interrupting the disease cycle between susceptible crops. Rotating away from corn can also give infected residue more time to break down before corn returns to the field.
The benefits can extend beyond disease management. More diverse rotations can support corn residue decomposition, nutrient cycling, soil structure and organic matter over time, all of which contribute to long-term field productivity and resilience.
Rotation isn’t equally effective against every disease, however. Some pathogens can survive longer or infect multiple crop hosts, so base your rotation decisions on each field’s specific disease history rather than treating rotation as a universal solution.²
Match corn hybrid selection to the disease history of each field
When you’re reviewing your corn hybrid selection this winter, prioritize hybrids with stronger ratings against the diseases that keep appearing in your field records.
Remember that “disease-resistant corn” doesn’t mean resistance to every disease. Resistance or tolerance needs to match the specific disease pressure you’ve seen in each field and the risks identified during winter planning.³
Consider disease resistance alongside yield potential, maturity and other agronomic traits your operation requires. The goal is to determine which traits matter most for each field and weigh disease resistance accordingly.
Build the fungicide plan around risk, not habit
Fungicides can sometimes be treated as an insurance policy across broad acreages. While that approach can produce results, it may not always be the most effective use of operating capital.
Identify higher-risk fields before planting to help you plan where fungicide applications may be most economically justified, then adjust those plans as weather and disease conditions develop.
The disease pressure you saw the previous year shouldn’t disappear into the yield monitor once harvest ends. Use winter to evaluate field history, residue, rotation, hybrid susceptibility and anticipated fungicide needs. You can’t predict next year’s disease pressure with certainty, but you can enter spring knowing which fields deserve the most attention.
Experts are available to help you make your corn hybrid selection decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
________________________________________________
Endnotes
- Bongard, Phyllis, et al. “Field Notes Talks Disease and Weed Management in a Very Wet Year.” Minnesota Crop News, University of Minnesota Extension, 9 July 2024,https://blog-crop-news.extension.umn.edu/2024/07/field-notes-talks-disease-and-weed.html
- Britton, Tim. “2024 Soybean Insect & Disease Control.” N.C. Cooperative Extension, Johnston County Center, 26 July 2024,https://johnston.ces.ncsu.edu/news/2024-soybean-insect-disease-control/.johnston.ces.ncsu.edu
- Telenko, Darcy E. P. “Corn and Soybean Disease Update.” Pest&Crop Newsletter, Purdue University Extension, 2024.Purdue Pest&Crop 2024 Issue 16
