Foliar fungicide application alters the culturable foliar fungal endophyte community in corn

Authors: Whitaker, Briana; Opoku, Joseph; KLECZEWSKI, NATHAN - Syngenta Biologicals

Submitted to: Phytobiomes Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2025
Publication Date: 2/12/2025
Citation: Whitaker, B.K., Opoku, J., Kleczewski, N.M. 2025. Foliar fungicide application alters the culturable foliar fungal endophyte community in corn. Phytobiomes Journal. https://doi.org/10.1094/PBIOMES-09-24-0089-R.
DOI: https://doi.org/10.1094/PBIOMES-09-24-0089-R

Interpretive Summary: The microbial communities living on crops greatly contribute to overall plant health and productivity. However, it is unclear how disease management practices unintendedly affect the plant microbiome. Corn is one of the most widely grown and economically important crops in the world. While foliar fungicides are frequently used to control corn diseases, little research has investigated the impact of these fungicide applications on the corn microbiome. Therefore, ARS researchers in Peoria, Illinois, in collaboration with scientists from Kernersville, North Carolina, evaluated the impact of a foliar fungicide on the fungal microbiome living in corn leaves at two locations in the midwestern United States. They identified moderate changes to the abundance and numbers of fungal species living in corn leaves. 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 microbiome.

Technical Abstract: Fungicides have been applied to crops for decades with the primary aim of managing fungal pathogens and disease. However, as interest in the plant microbiome has grown, so too have questions about potential non-target 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 dentcorn ear leaves at two midwestern US locations. The impact of the fungicide application on FFE community structure was highly dependent on spatial effects. Additionally, alpha diversity metrics that accounted for 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.