Southern Corn Rust was found for the 1st time this season in Georgia corn yesterday in a Wayne County field. It was an early planted field with plants between the R3-R4 growth stage.
Dr. Bob K:
Who is at greatest risk?
Answer. All growers in SE GA with irrigated corn at or very near tassel growth stage. Growers in SW GA are also likely at high risk.
Why is southern rust early this year?
Answer. I think because of warm La Niña Winter and very warm conditions now.
Will [we] make money if [we] spray a fungicide for rust?
Answer. All I can promise is that it will cost somewhere between $15 and $30 per acre including airplane. I can also say that if this disease gets in early, as in Wayne Co, I think it could easily rob the grower of 100 bu/A yield.
Will we need to spray twice- now and 3 weeks later?
Answer. Possibly. But if you get the fungicide out in a timely manner, a second application may not be needed and, if it is, you may be able to use a less expensive product.
What should [be] sprayed?
Answer. I prefer [we] use a fungicide that is a mixed mode of action product combining different fungicides. Yes, I have had very good success with Trivapro, Headline Amp, and Veltyma. But I have also seen strong results from other products like Aproach Prima, Stratego YLD, Delano, Fortix, Lucento, etc.