Managing Corn Leaf Diseases for 2018

Categories: HARVEST, CORN
Photo Caption: Blocky, tan lesions in the crop’s leaves are often a symptom of gray leaf spot.

Farmers in parts of Iowa may be feeling the yield-impacting effect of corn leaf diseases this season, especially in light of the cool, wet spring which created the perfect environment for disease inoculation in some areas. Common leaf diseases this season include gray leaf spot and northern corn leaf blight (NCLB). Since both of these diseases can overwinter in fields, now is the time to get ahead of potential damages for the 2018 growing season.

According to Iowa State University, you can identify
gray leaf spot in your fields by looking for tan, narrow lesions along the plant’s leaf. Symptoms will usually start to show around 2-3 weeks before tasseling. NCLB, Iowa State University also notes, creates visual symptoms on the leaves. Farmers with NCLB will see long, elliptical-shaped lesions in their corn leaves. In wetter conditions, the pathogen may also create dark gray spores on the lower leaf surface.

If you had either disease in your field this season, consider the following adjustments for your 2018 management plans:

  • Crop rotation: Since both diseases are limited to corn crops, farmers are advised to consider rotating to soybeans or another non-host crop for the following season. As mentioned, both diseases overwinter – so if you see it now, you may also see it next year. Rotating corn-on-corn fields to a different crop will help future corn crops be less susceptible to the disease.
  • Residue management: Corn debris left behind after harvest can potentially cause corn fields to become infected again next season. To prevent a repeat occurrence, consider baling leftover corn or plowing infected corn into the ground.
  • Hybrid selection: As you begin to think about which hybrids you are going to plant next season, you may want to consider selecting Golden Harvest hybrids that are rated high for NCLB and gray leaf spot if these diseases posed a problem for you this season.

Keep in mind that the severity of both diseases depends on a combination of hybrid susceptibility and environmental conditions. Spores from either disease are usually carried in the wind, or can splash up from the soils onto the plants during a particularly rainy spring. Make sure you’re prepared to tackle NCLB or gray leaf spot, just in case 2018 brings favorable conditions.

Contact your local independent Golden Harvest Seed Advisor with questions or for additional agronomic insights.

Photos are either the property of Syngenta or used under agreement.
Syngenta hereby disclaims liability for third-party websites.

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