Foliar Fungicide Application Alters the Culturable Foliar Fungal Endophyte Community in Corn

Fungicides have been applied to crops for decades with the primary aim of managing fungal pathogens and diseases. However, as interest in the plant microbiome has grown, so too have questions about potential nontarget effects of pest management on native microbiota. Corn is one of the most widely grown and economically important crops in the world, but little research has investigated the role of fungicide applications, particularly foliar fungicides, on the corn microbiome. Here, we used a culture-dependent approach to identify whether a systemic, multi-mode-of-action foliar fungicide would alter the foliar fungal endophyte (FFE) community in dent corn ear leaves at two Midwestern U.S. locations. The impact of the fungicide application on FFE community structure was highly dependent on spatial effects. Additionally, alpha diversity metrics that accounted for the relative abundance of fungal taxa were most affected by fungicide treatment. By contrast, FFE isolation frequency from leaf fragments was not dependent on fungicide treatment, suggesting no net culturable fungal biomass changes. Ultimately, this work will serve as a resource for agronomists and pathologists seeking to understand the role of traditional crop management practices on the corn phytobiome. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2025.