Corn Disease

C.O.R.N. Newsletter Articles

  1. Gibberella ear rot in corn
    Author(s): Jason Hartschuh, CCA , Author(s): Pierce Paul

    Ear rots and mycotoxins: Ear rots are beginning to show up in pockets across the state, leading to concerns about mycotoxin contamination of grain. So far, we have received images and samples with Gibberella, Diplodia, Fusarium, and Trichoderma ear rots, four of the most common ear rots in the state. Of these, Gibberella (GER) and Fusarium ear rots are of greatest concerns, since grain harvested from affected fields will be contaminated with mycotoxins, particularly vomitoxin in the case of GER.

    Issue: 2022-34
  2. Author(s): Pierce Paul

    Most of the corn across the state of Ohio is now between the late-R1 (silking) and late-R3 (milk) growth stages, with a few late-planted fields at late vegetative stages. Concerns about tar spot, but more likely, a sense of security provided by relatively high grain prices have led to several fields being sprayed with a fungicide at or shortly after R1 and questions being asked about spraying additional fields that are now at mid reproductive stages (between late-R2 [kernel blister] and R3 [milk]) of development.

    Issue: 2022-27
  3. Author(s): Pierce Paul , Author(s): Jorge Valle

    Tar spot is relatively easy to diagnose based on visual symptoms. So as the crop develops you should begin scouting fields to determine: 1) if tar spot is present, 2) estimate how much is there, 3) determine whether it is increasing over time, and 4) decide whether you should consider making a fungicide application. Walk down about 25-ft-of-row at 10 to 15 locations across the field and examine a pair of plants at every 10 steps for the present of tar spot.

    Issue: 2022-22
  4. Author(s): Pierce Paul

    Q: Is tar spot a late-season disease in Ohio?

    Issue: 2022-21
  5. Corn leaf displaying symptoms of Northern corn leaf blight
    Author(s): Stephanie Karhoff, CCA , Author(s): Elizabeth Hawkins

    Preventing significant yield losses from disease is likely on the forefront of growers’ minds following the 2021 growing season. A new product available to growers is FMC’s fungicide Xyway™ LFR®. OSU Extension eFields program is partnering with growers to conduct on-farm trials evaluating the effect of an at-plant soil application of flutriafol (Xyway) on corn health and yield. Information from this trial will be used to improve corn disease management recommendations for growers throughout the state.

    Issue: 2022-11


  1. Abnormal Ear Diagnosis Poster,  ACE-1. Farmers frequently encounter abnormal corn ears in their fields when the crop has experienced a major stress, such as drought, temperature extremes, disease, insect injury, or misapplied chemicals. These abnormalities often affect yield and grain quality adversely. In this poster, ten abnormal corn ears with distinct symptoms and causes are highlighted. The purpose of the poster is to help corn growers and agricultural professionals diagnose various ear disorders.

  2. Corn Disease Management in Ohio, Bulletin 804. Five to 15 percent of Ohio's corn crop is lost to disease each year, amounting to nearly $100 million in lost farm income. Corn diseases include seedling diseases, leaf blights, stalk rots, ear and kernel rots, and viruses. This bulletin describes the disease symptoms, provides color images, gives the environmental factors favoring the disease, the method of transmission and infection, and management options for the major diseases affecting corn in Ohio.

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