Corn planting in Kentucky got off to a strong start in 2023, with farmers taking advantage of early to mid-April planting opportunities. However, the combination of cool weather and low soil temperatures has resulted in delayed emergence and increased risks of seedling diseases in corn fields across the state.
Seedling diseases in corn are caused by various fungi or fungal-like organisms that thrive in cool and wet soil conditions during and after planting. The extended period of cool, wet soils slows down plant growth and provides pathogens with more time to infect and damage seedlings. Although standard corn fungicide seed treatments offer some protection against seedling diseases, their effectiveness typically lasts for only a few weeks. Corn that was planted several weeks ago may now face an elevated risk of seedling diseases.
Key symptoms of seedling diseases include poor emergence within specific areas or rows of a field, patchy stands, and stunted plants. These signs are often first observed in poorly drained or ponded sections of the field, as well as areas with heavy or compacted soils. Infected seeds may rot after germination, hindering emergence and resulting in uneven plant distribution. Affected plants that do emerge may exhibit yellowing, stunted growth, and discolored roots. In severe cases, extensive plant loss can occur, leading to reduced stand density.
Accurate diagnosis of the specific organism responsible for seedling disease issues is challenging but essential for effective management. Submitting samples to the University of Kentucky Plant Disease Diagnostic Laboratory through a county agent can aid in obtaining an accurate diagnosis.
Reducing the risk of corn seedling diseases is possible by planting into dry soils with temperatures above 50°F. However, planting in less-than-ideal conditions is often necessary, making the diagnosis of seedling disease issues crucial for future management strategies. Fungicide efficacy varies depending on the active ingredient and targeted organisms, so tailored treatments may be necessary for fields with a history of severe losses from specific seedling diseases.
For comprehensive information on corn seedling blights and management strategies, refer to the University of Kentucky Extension Publication, "Seedling Diseases of Corn" (PPFS-AG-C-02).
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Categories: Kentucky, Crops, Corn