This time of year southern rust can be found at any moment. This morning Dr Bob Kemerait updated Extension agents and corn growers about the current southern rust situation (June 3,2025).
Yesterday ( June 2, 2025) southern corn rust has now been found in a single field Jackson County, Florida but is not yet known in Georgia. Given that a) the rust found in a neighboring county to Seminole Co GA where substantial corn acreage is located and b) the rust had likely been in the field for two or more weeks, there is general concern for Georgia field corn in extreme SW GA.
Okay Bob. Southern rust has been found. Do you have any suggestions on what to do?
Would I spray corn at tassel (and later) growth stages in counties like Seminole and Early and Decatur?
1) if I have a good scout hunting for disease in my corn and nothing is found, I would consider delaying until rust is further detected either in my fields or in the county.
2) if I do not have a good scout looking at my corn, I would spray a fungicide at tassel or beyond as I a) have great respect for the disease and b) the weather over the next 10 days is favorable for spread.
3) What would I spray? I strongly encourage spraying products that mix more than one mode of action. This increases broader spectrum efficacy and length of protective window.
4) Should I spray my corn in Colquitt Co? Dr Bob’s answer is, “They certainly can now, but until we find a breakout of rust from Florida, I think spraying outside of extreme SW GA is a bit premature and sets you up for possibly spraying twice. But tassel is the time to make informed decisions.”
If you have questions about the current disease situation in your area please contact your local county Extension agent.