Aflatoxin Accumulation In Corn Influenced By Cultural Practices In The Us Mid-South

Aflatoxin contamination in corn (Zea mays L.) grain negatively affects human and animal health. This research was conducted to determine if interactions among cultural practices influence aflatoxin accumulation on inoculated and naturally infested corn. Season-long irrigation thresholds (full irrigation at -50 kPa vs. deficit irrigation at -125 kPa), planting date (late March vs. late April), and hybrid selection (conventional short-season, drought-tolerant full-season, or conventional full-season) were evaluated for their influence on aflatoxin accumulation. Experiments were conducted on a Marietta fine sandy loam and a Leeper silty clay loam near Starkville and Verona, MS, in 2016 and 2017, respectively. Needle-inoculated and noninoculated ears were harvested from each plot. Noninoculated samples indicated that year (p = .0013) and planting date x hybrid type interaction (p = .0263) affected aflatoxin accumulation. The first year of the study produced greater average aflatoxin levels than the second year due to hotter and drier growing conditions for noninoculated samples. Pooled over years, planting later only affected conventional short-season hybrids, increasing aflatoxin levels by 77% in naturally infested corn. Inoculated samples were affected by a year x planting date interaction (p = .0044) and a planting date x hybrid type interaction (p = .0032). Planting in March 2016 increased aflatoxin more than threefold compared with planting in April, whereas there was no difference between planting date in 2017. Overall, year, planting date, and hybrid type affected aflatoxin levels.