Correlating Fusarium Presence with DON Production in Silage Corn
Field investigation of how Fusarium graminearum colonization in corn ears and stalks drives DON accumulation — with implications for dairy feed safety.
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The question
Does the amount of Fusarium graminearum DNA present in different parts of a corn plant predict how much deoxynivalenol (DON) ends up in silage? And does the answer differ between hybrid market classes — specifically, do brown midrib (BMR) and conventional silage hybrids behave differently?
These questions matter because DON in dairy feed depresses milk production and feed intake, yet the relationship between where fungi colonize corn plants and where toxin accumulates was not well understood, especially under Wisconsin field conditions.
Approach and methods
Field trials were conducted across two seasons (2020–2021) at the Arlington Agricultural Research Station in Arlington, Wisconsin. Both a BMR hybrid and a conventional hybrid were grown under multiple fungicide management scenarios — foliar applications at silking (R1), in-furrow applications at planting, and combinations — alongside untreated controls.
Disease scouting and plant partitioning — Above-ground disease severity (including tar spot, Gibberella ear rot, and stalk rot) was visually rated using standard area diagrams. At harvest, whole plants were partitioned into ear and stalk fractions. Partitioning ears from stalks was critical to understanding whether fungal colonization and toxin production occurred independently in each tissue — which turned out to be the key finding.
Quantifying fungal presence (qPCR) — DNA was extracted from homogenized tissue samples using CTAB-based protocols. Species-specific primers targeting F. graminearum were used in quantitative PCR (qPCR) to measure fungal DNA concentration (picograms per microliter) in both the ear and stalk fractions. This allowed direct comparison of fungal load across tissues, hybrids, and treatments.
Toxin quantification (LC-MS/MS) — DON and its modified form deoxynivalenol-3-glucoside (DON3G) were quantified in chopped whole-plant silage samples and in partitioned ear and stalk tissues using liquid chromatography–tandem mass spectrometry (LC-MS/MS). This method provided the sensitivity needed to detect DON3G, which is often missed by routine immunoassay-based testing.
Key findings
F. graminearum colonization and DON accumulation occurred independently in ears versus stalks — they do not necessarily track together. The conventional hybrid consistently showed lower F. graminearum DNA concentration and lower DON in ears compared to its stalks, while the BMR hybrid showed elevated colonization and toxin in both fractions. Hybrid class, not fungicide treatment, was the dominant driver of DON outcomes in whole-plant corn silage.
Fungicide applications were inconsistent in their effects across years — a reminder that management tools that work well for foliar disease have limited reach for ear rot and stalk rot, where infection pathways differ.
Published work
Chibuogwu, M. O., Groves, C. L., Mueller, B., & Smith, D. (2024). Effect of fungicide application and corn hybrid class on the presence of Fusarium graminearum and the concentration of deoxynivalenol in ear and stalk parts of corn (Zea mays) used for silage. Plant Disease, 108, 2090–2095.
doi.org/10.1094/PDIS-12-23-2662-RE ↗
Chibuogwu, M. O., Mueller, B., Groves, C. L., Tenuta, A. U., Chilvers, M. I., Wise, K. A., & Smith, D. (2025). Where’s DON? Understanding where deoxynivalenol accumulates in corn silage. Crop Protection Network, CPN-5018.