I have just got back from the ISU Southeast Research Farm near Crawfordsville. I was assessing my Cardinal fungicide trial. With all the reports of northern corn leaf blight (NCLB) in SE IA I decided it was probably worth the drive to get some "disease at VT" data.
The crop in the trial was at R1. It was hot. Pollen was shedding. The perfect time to spend a few hours wandering through a corn field. Foliar fungicide treatments had been applied last week (VT) and some plots had applications at V5-V6.
I was so disappointed! Yes, we saw NCLB .....but the incidence was very low. I estimate we saw 0 to 4 plants with 1-2 lesions per plot. When you consider the plots are 55 ft long, this means we looked at approximately 180 plants. Thus the incidence was up to 2 percent. Disappointing from a plant pathologists perspective!!! With such low disease incidence, it was impossible to detect treatment differences. In fact, in some of the non-sprayed control plots we could not find the disease.
In the past week I have walked several fields of corn in southern and central Iowa. There are definitely some hot spots, around Knoxville, for instance. There are also other areas where the disease is more of a novelty. What this tells me is scouting is very important this year. Even if you are growing susceptible hybrids, you may have escaped the disease thus far.