Use best management practice to manage corn diseases

A fungicide seed treatment can provide a healthy start for seedlings.
A fungicide seed treatment can provide a healthy start for seedlings.

Common diseases affecting the leaves, stalks and roots, seeds and seedlings and other structures threaten corn production throughout the season. Infection by most stalk rot organisms, both fungal and bacterial, can occur early in the season but become obvious during 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.

Fungal or bacterial?

Corn diseases caused by fungi include anthracnose, gray leaf spot, eyespot, northern and southern corn leaf blights, Rhizotonia root root, Fusarium stalk rot, Gibberella stalk rot, Diplodia stalk rot, charcoal rot and common smut. Common and southern rust are carried by windborne fungal spores and commonly affect seed corn and sweet corn. Goss’s leaf blight, Stewart’s wilt and bacterial stalk rot are caused by bacteria.

Best management practices

Best management practices help minimize the potential for fungicide resistance, which can occur when heavy reliance is placed on controlling diseases with one chemistry class. Best management practices for controlling diseases include cultural practices, planting disease-tolerant hybrids and applying fungicides with multiple modes of action.

Cultural practices

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, too.

Plant disease-tolerant hybrids

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

Fungicide applications

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. For farmers, a fungicide decision is a matter of considering his production practices, disease history in his fields, commodity prices, proper timing and risk management.

Fungicide timing and yield bump

Stratego® YLD fungicide from Crop Science controls a broad spectrum of diseases; it combines the latest in triazole technology, complemented with a powerful strobilurin chemistry. This versatile fungicide can be applied early season and/or at tassel. The early-season application delays the onset of infection, which protects the canopy and stalk. The tassel application protects the photosynthetic engine. Both applications are especially important for growers who are pushing for high yield production and/or farming in an area with a disease history.

Yield increases over untreated corn have been consistently demonstrated, with a nearly 7-bushel-per-acre increase with use of an early-season application and a nearly 12-bushel increase with use of a tassel application. Growers have been shown to gain 15 bushels when using both the early and tassel applications.  

Keep in mind that an early-season fungicide application can be made via tankmixing with a postemergence herbicide, increasing the utility of the trip across the field.  This practice provides early season protection of the stalks and leaves, leading to a yield bump to your crop.

For more information on corn disease management solutions from Bayer, contact your local Crop Science US representative.  

Before applying any fungicide to your field, please read the entire label for the best possible results and to confirm that the product is effective on the disease you need to control. Not every product is suitable for every situation, and correct application technique will ensure the best results.

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