Corn Disease

C.O.R.N. Newsletter Articles

  1. Author(s): Pierce Paul , Author(s): Felipe Dalla Lana da Silva , Author(s): Dee Jepsen

    Moldy Field CornHarvesting, Sampling, and Testing: This year, slow grain dry-down, delayed harvest, and late-season rainfall have led to fairly high levels of one or more ear rots (Gibberella, Fusarium, Diplodia and Trichoderma) in some corn fields.

    Issue: 2020-38
  2. Author(s): Pierce Paul

    Corn harvest is progressing very slowly across the state as the crop is taking unusually long to dry down this year. The longer the crop stays in the field, there greater the risk of late-season diseases such as ear and stalk rots, especially if it continues to rain. Stalk rot often refers to a combination of several interrelated problems, including stalk breakage, stalk lodging, premature plant death, and root lodging. Several factors may contribute to stalk rot, including extreme weather conditions, inadequate fertilization, problems with nutrient uptake, insects, and diseases.

    Issue: 2020-36
  3. Author(s): Pierce Paul , Author(s): Felipe Dalla Lana da Silva

    Over the last two weeks, we have received samples or pictures of at least two different types of corn ear rots – Gibberella and Trichoderma. Of the two, Gibberella ear rot (GER) seems to be the most prevalent. Ear rots differ from each other in terms of the damage they cause (their symptoms), the toxins they produce, and the specific conditions under which they develop. GER leads to grain contamination with mycotoxins, including deoxynivalenol (also known as vomitoxin), and is favored by warm, wet, or humid conditions between silk emergence (R1) and early grain development.

    Issue: 2020-34
  4. Author(s): Pierce Paul , Author(s): Felipe Dalla Lana da Silva

    As was the case in 2018 and 2019, tar Spot, a relatively new disease of corn, is again being reported in some fields. However, as was the case in the last two years, the disease is only now showing up, with the first reports coming in well after R5 (the dough growth stage). This is likely too late for it to impact grain yield and quality, as the greatest damage in terms of yield loss usually occurs when leaves are severely affected before grain fill is complete.

    Issue: 2020-34
  5. Author(s): Pierce Paul , Author(s): Felipe Dalla Lana da Silva

    Tar Spot, a new disease of corn caused by the fungus Phyllachora maydis, was reported for the first time in Ohio at the end of the 2018 growing season. At that time, it was found mostly in counties close to the Indiana border, as the disease continued to spread from the middle of country where it was first confirmed in 2015. Over the last few weeks, there have been several new, confirmed report of Tar Spot in Ohio, this time not only in the northwestern corner of the state, but also from a few fields in central and south-central Ohio.

    Issue: 2020-03

Publications

  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.

  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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