Southern corn rust was confirmed yesterday (June 1) in Wayne County on early planted corn at R3/R4 growth stage. The corn crop in Colquitt County ranges from V10 to VT. Growers in SW Georgia need to be on high alert for Southern rust. Currently (June 2, 2022) no southern corn rust has been found in Colquitt County sentinel plots. You can view all confirmed identifications of Southern corn rust and soybean rust at the two below links:
https://corn.ipmpipe.org/southerncornrust/
https://soybean.ipmpipe.org/soybeanrust/
Below are a few comments from Dr. Bob Kemerait, UGA Plant Pathologist, on the subject of corn fungicides.
- Single mode-of-action products like Tebuconazole, Quadris, and Domark are “good” but have a two-week protective window.
- Mixed mode of action products like Stratego YLD, Aproach Prima, Delaro, and a number of other fungicides have better efficacy and a three-week protective window than do single mode of action products. Product like these work well, especially when risk is heightened but fields are spray before rust is established in a field.
- I am always asked, and I am careful in my words, “Which fungicide is best for rust on corn?” All mixed mode of action products work BEST and often WELL when sprayed early ahead of disease infection and development. It is my experience that the products that have the biggest impact on southern corn rust are Trivapro, Headline AMP and Veltyma. They tend to look very good in my trials when rust is particularly severe; all fungicides can perform well when applied ahead of disease.