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ARS Home » Southeast Area » Stoneville, Mississippi » Biological Control of Pests Research » Research » Publications at this Location » Publication #429611
Title: Aspergillus flavus populations in matrices of the corn agroecosystem

Author
item Weaver, Mark
item BREWER, MICHAEL - Texas A&M University
item Park, Lilly
item BRADICICH, PIUS - Texas A&M University
item Reddy, Krishna

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2026
Publication Date: 5/7/2026
Citation: Weaver, M.A., Brewer, M.J., Park, L.C., Bradicich, P.A., Reddy, K.N. 2026. Aspergillus flavus populations in matrices of the corn agroecosystem. Plant Disease. https://doi.org/10.1094/PDIS-09-25-2006-RE.
DOI: https://doi.org/10.1094/PDIS-09-25-2006-RE

Interpretive Summary: If possible, please also edit the Technical abstract to read: Infection of corn by the pathogen Aspergillus flavus can result in the contamination of the grain with aflatoxin, a potent, regulated mycotoxin. A. flavus has high genetic diversity, even within a single field, but it is unknown if the population is homogenous among the different matrices of the corn agroecosystem or if there are discernable subpopulations. We collected isolates of A. flavus from two sites for two years from soil, grain, corn silks, and Helicoverpa zea moths and larvae. This collection of over 1000 isolates of A. flavus were screened and characterized based upon aflatoxigenic potential, sclerotial morphotype and 17 simple sequence repeat (SSR) markers. The collection from the Corpus Christi, Texas study site had a higher frequency of aflatoxigenic isolates than the collection from Stoneville, Mississippi. The genotype of a commercially available biocontrol isolate of A. flavus was present at both study sites, but was 5 times more abundant at Stoneville, Mississippi than at Corpus Christi, Texas. SSR-based population genetics indicated that the A. flavus populations collected from various matrices were not differentiated and that there appeared to be significant gene flow among the populations within each site.

Technical Abstract: Infection of corn by the pathogen Aspergillus flavus can result in the contamination of the grain with the with aflatoxin, a potent, regulated mycotoxin. To better understand the population-level biology of this fungus we collected over 1000 isolates of A. flavus from corn kernels, corn silks, corn earworm moths and larvae and from soil and air samples from Corpus Christi, Texas and Stoneville, Mississippi during two growing seasons. These fungal isolates were characterized phenotypically and genetically. A greater percentage of isolates from the Texas site were aflatoxin-producing than the population from Mississippi. The Mississippi population, in contrast, had a high occurrence of isolates that were genetically similar to, or identical to, a known, commercialized biocontrol isolate of A. flavus. The populations from various sources within the corn field were not genetically distinct, indicating that the A. flavus in a single field may represent a single, undifferentiated population.