Dr. Kemerait
As from my e-mail yesterday, 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 by consultant is in a neighboring county to Seminole Co GA where substantial corn is grown 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.
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) Jeremy asked, “Should my Colquitt Co growers spray their corn?” My 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.”
