Southern Rust Spreads Across Corn Fields This Season
Published: 08/28/2025
Southern rust of corn has become a widespread issue during the 2025 growing season, fueled by persistent warm and wet conditions across the Midwest. The disease, caused by Puccinia polysora, has been confirmed in multiple states and is now considered a top foliar disease concern. It spreads rapidly under high humidity and temperatures around 80°F, especially in late-planted fields and susceptible hybrids. The southern rust fungus uses the plant’s nutrients for growth and reproduction, which affects grain fill and ultimately reduces yields.
Management recommendations emphasize timely scouting and fungicide application during the VT (tasseling) to R3 (milk) growth stages. Southern rust does not overwinter in crop residue or soil, as the pathogen relies on windborne spores from tropical regions to re-establish each season. Planning for next year should include reviewing recommended planting time and in-season management decisions to reduce future disease risk.
Southern rust has become a widespread issue this season, fueled by persistent warm and wet conditions.
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