Southern Rust Reported

Thanks to the cooperative efforts between UGA Cooperative Extension Service and our friends with Pioneer, UGA Extension Pathologist, Dr. Bob Kemerait, reports two cases of SOUTHERN CORN RUST: 1) Early County (Agent Brian Cresswell) and in Florida just below the Echols County (Agent Justin Shealey).

Below are pictures of southern rust attached that Rome Ethredge took from the Early County sample and points from Dr. Kemerait to consider:

1. SOUTHERN CORN RUST is early this year.
2. Currently, southern rust likely is a threat to corn across the southern part of the state.
3. Southern corn rust is out most important disease of corn.
4. Rain is back in the forecast for late this weekend; early next week, which will be favorable for development of rust.
5. I think that corn that is approaching (or has passed) the tassel growth stage is worth protecting if the yield potential is there. I generally would wait to spray for southern rust until your crop is approaching tassel.
6. Triazole fungicides (like tebuconazole) are effective against rust (but lack the broader activity against northern corn leaf blight) and have a two week protective window.  Strobilurin products and combination strobilurin/triazole of strobilurin/SDHI (Priaxor) have 3 week protective intervals and also a broader spectrum of activity.
7. Northern corn leaf blight is generally in check this year.