The majority of our corn crop is at VT or R1 and this is the appropriate time to start making the decision whether or not to spray a fungicide.
Observations from South Carolina corn fields:
At the Edisto REC Dr. Plumblee and I have walked several fields and the corn is very clean when it comes to foliar diseases.
Charles Davis reported that most of the corn fields he has been in are free of significant levels of foliar diseases. He has seen a trace of Gray leaf spot in some fields.
Jonathan Croft has been looking at corn fields and they are relatively free of significant levels of foliar diseases; he has seen some scattered traces of low levels of Curvularia leaf spot and gray leaf spot.
Joe Varn has a similar report, most corn fields he has looked at are very clean and free of foliar diseases.
Joe is also our resident pro at finding soybean rust. He has been looking at soybeans and kudzu but so far, no soybean rust detected on either soybean or kudzu in South Carolina.
Reports from Dr. Kemerait in Georgia:
The reports from Georgia are that “Southern corn rust is widely spread across southern Georgia” and they are seeing common rust on corn in some fields.
Dr. Kemerait also reports that “soybean rust is widely distributed in kudzu (in Georgia).
I think everyone knows that the weather system moving in from the Gulf of Mexico is creating the perfect circumstances to move all types of diseases into South Carolina. Depending upon what this storm delivers to us in term of rain we may see a significant increase in many diseases. It looks like growers should be prepared to spray fungicides on their corn in the next week or two to protect against Southern rust and other foliar diseases if they have good yield potentials.
As far as soybean rust is concerned you should not be concerned about this in any field until that individual field has flowered. We normally do not have to deal with soybean rust until late July and August. We have the expert rust finder, Joe Varn, out there looking, so we are in good hands for rust detection.
Contact your county agent or one of us if you have any questions.