Identify Corn Bacterial Diseases to Plan for Next Year

Categories: GROWING, CORN
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Corn bacterial diseases reduce green tissue surface area, decrease yield potential and can lead to late-season stalk rot.

Goss’s wilt and leaf blight, bacterial leaf streak and holcus spot are common bacterial diseases. Knowing which of these diseases are present in your fields and at what levels can give you insights on next season management.
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Goss’s wilt and leaf blight
Goss’s bacterial wilt had historically been confined to the Great Plains. In recent years, it has spread through the Midwest, causing considerable damage. The leaf blight phase is more common and harmful to corn than the wilt phase. It typically infects leaves damaged by hail, sand-blasting and rain.

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Since BLS is so new, there is little data about its impact on corn productivity. However, researchers have found it overwinters in corn residue, and they suspect it enters the plant through natural openings, such as the stomata, and occasionally through wounds. The good news is no one has reported a systemic infection with this pathogen, which could cause vascular wilt. This likely indicates BLS will not have as much yield impact as Goss’s wilt. Unfortunately, the injury is still often severe enough to cause some yield loss.

  • Symptoms:
    • In the leaf blight phase, long, light tan or yellow to gray lesions with irregular borders running parallel to veins form
    • Lesion margins appear water-soaked with small, dark green spots
    • Ooze appearing like dry varnish is often seen in lesions
    • During the wilt phase, symptoms include wilting and stalk degradation, which turns orange or brown, is water-soaked and contains a slimy interior
  • Environmental triggers:
    • Warm temperatures over 80o F
    • Continuous corn
    • Reduced tillage
Bacterial leaf streak
Bacterial leaf streak (BLS) is a new corn leaf disease first confirmed in Nebraska during 2016, which quickly spread from Minnesota to Texas, and Colorado to Illinois. Disease symptoms are pictured below.


  • Symptoms:
    • Narrow lesions parallel to leaf veins, similar to gray leaf spot (GLS)
    • Lesion edges are usually wavy and differ from the straight GLS edges
    • Lesions typically form earlier than GLS as BLS prefers cooler development conditions
    • Lesions are yellow, tan or brown-striped, and often yellow when backlit
  • Environmental triggers:
    • Irrigation and wind-driven rain
    • Warm, humid conditions
    • Continuous corn fields with considerable residue
    • Fields with history of bacterial leaf spot
    • Reduced tillage

Holcus Spot
Holcus spot is a bacterial disease initially found on young plants. It overwinters in corn and can have a wide range of grass and dicot weed hosts. Holcus spot typically infects corn early in the season, following high winds and thunderstorms.

  • Symptoms:
    • First appears as water-soaked, dark green lesions on the tips of lower leaves
    • Later develops into round or elliptical tan or white spots, with a reddish brown border and yellow halo
    • Looks like paraquat injury, or has a consistent pattern of geometric shapes
  • Environmental triggers:
    • Extended wet and warm weather
    • No-till fields
    • Continuous corn

Bacterial disease management
Unfortunately, there isn’t a fungicide to help control bacterial diseases, including Goss’s wilt, leaf blight and BLS. However, planting hybrids with good to excellent disease tolerance and rotating crops helps manage pressure. Golden Harvest hybrids are routinely screened for Goss’s wilt tolerance, and ratings are available on the hybrid product pages. After BLS was identified in 2016, Golden Harvest has consistently screened hybrids for tolerance to the disease and will start providing ratings in the near future.

Contact your 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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