Hybrid, plant population, and nitrogen treatment: Impact on preharvest fumonisin contamination in corn ( Zea mays )

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Abstract Fumonisins are mycotoxins produced by the fungal pathogen, Fusarium verticillioides , and they are widespread in corn ( Zea mays L.), especially in the Southeastern United States. While there are several post‐harvest mitigation strategies to reduce fumonisin, there are limited studies testing pre‐harvest strategies. Therefore, field studies were conducted at two locations in Mississippi to examine the impact of agronomic practices in mitigating fumonisin accumulation in corn. The experiments were set up in a split‐plot design, with nitrogen (N) (0, 112, 224, and 336 kg N ha −1 ) as main plot factor and combination of plant populations (PPs) (75,000, 87,500, 100,000, and 112,500 plants ha −1 ) and corn hybrids (H) with and without Bacillus thuringiensis ( Bt ) traits (DKC70‐27 and 70‐25, respectively, where DKC is Dekalb corn) as subplot factors. Ten ears per plot were inoculated with F. verticillioides for subsequent post‐harvest fumonisin quantification. In 2024, fumonisin accumulation was significantly influenced by H × PP interaction ( p < 0.05) and ear rot severity was influenced by N × PP interaction ( p < 0.05) in Starkville, whereas in 2023, only the main treatments affected fumonisin accumulation in Starkville and Brooksville. Overall, the Bt hybrid showed significantly lower ear rot severity and fumonisin accumulation. Moreover, fumonisin accumulation decreased with an N rate of 112 kg N ha −1 in Starkville, without any noticeable differences at higher N rates. In summary, this study identified that the best preharvest strategy to mitigate fumonisin includes selecting hybrid with Bt traits for reducing insect injury to the ear, maintaining a planting density between 75,000 and 87,500 plants ha −1 , and applying at least 112 kg N ha −1 for minimizing nitrogen deficiency.

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