Managing Corn Disease? These 4 Questions Can Help


Disease can threaten corn production throughout the season, from common diseases that affect leaves, stalks and roots to others that put seeds and seedlings at risk.

Infection by stalk rot organisms can occur early in the season, but visual symptoms may not appear until grain fill. Stalk rots can cause significant yield loss when the disease causes plants to deteriorate prematurely, resulting in poor ear fill or light test weight grain. Lodging can also cause heavy yield losses.

So what can you do to protect your crop from disease? Best management practices can help. Ask yourself these four questions:

Is it fungal or bacterial?

Corn diseases caused by fungi include anthracnose, gray leaf spot, eyespot, northern corn leaf blight, southern corn leaf blight, Rhizotonia root root, Fusarium stalk rot, Gibberella stalk rot, Diplodia stalk rot, charcoal rot and common smut. Common and southern rust are carried by wind-borne fungal spores and commonly affect seed corn and sweet corn. Timely fungicide applications can help control these diseases. Diseases caused by bacteria, such as Goss’s leaf blight, Stewart’s wilt and bacterial stalk rot, do not respond to fungicides.

What hybrids should I plant?

Before planting, farmers should take a field’s specific disease history into account and then match it with a resistant corn hybrid.

What cultural practices do I have planned?

Because several disease organisms survive in infected residue from crop to crop, there are several cultural practices that can help break this cycle and diminish disease pressure. For example:

  • Crop rotation allows surface corn residue to break down, reducing bacteria and fungal inoculum.
  • Incorporating corn residue into the soil can further reduce the disease pressure the following season.
  • Good weed control removes disease hosts.

When should I use fungicides?

For growers, a fungicide decision is a matter of considering the hybrid/cultivar planted, crop rotation, disease history in his fields, and environmental conditions. A seed treatment provides great insurance against early fungal diseases, especially in cool and damp spring conditions, and helps seedlings get off to a vigorous start. Also, timely foliar fungicide applications can help protect corn plants from fungal infections throughout the season.

Applying fungicides with multiple modes of action, such as Delaro® and Stratego® YLD can help minimize the potential for fungicide resistance, which can occur when heavy reliance is placed on controlling diseases with one chemical class.

Corn Disease Solutions from Bayer

Achieve your personal best yield with help from Delaro® fungicide from Bayer. Its advanced formulation delivers unmatched, broad-spectrum disease control, best-in-class dual mode of action residual and improved plant health. This versatile fungicide has application flexibility — at-tassel timing (VT to R2), in combination with a herbicide (V4 to V7) and/or in between (V8 to VT). Delaro can be applied by air, ground or by chemigation and can be mixed with adjuvants, herbicides, insecticides and micronutrients.

Stratego® YLD fungicide from Bayer controls a broad spectrum of diseases; it combines the latest in triazole technology with a powerful, complementary strobilurin chemistry. This versatile fungicide can be applied early season and/or at tassel. The early-season application delays the onset of infection in the middle of the canopy and fights infections of the stalk. The tassel application protects the photosynthetic engine, the ear leaf and the surrounding leaves. Both applications are especially important for growers who are pushing for high yield production and/or farming in an area with a disease history. For cost efficiency, the early season application may be made via a tankmix with a postemergence herbicide, saving an additional pass across the field.

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