Whether to or not to spray corn continues to be a pressing issue. We still have not observed southern corn rust in Georgia and there has not been a lot reported in Florida. Dr. Kemerait is still not pushing hard for us to make a fungicide application, but he also states that it is a good idea to be cautious. Stink bug pressure has not been terrible, but we still need to be scouting. If you do decide to make a fungicide application, it would be wise to go ahead and throw a pyrethroid (likely bifenthrin) to knock out any stink bugs. Corn is at highest risk for stink bug damage during early ear formation before silking.
All the corn I have looked at in the county looks great so far. Very little stink bug pressure and not much disease. Dr. Kemerait has confirmed cases of Northern Corn Leaf Spot, Northern Corn Leaf Blight, and Southern Corn Leaf Blight in the state so far. Usually these diseases do not justify a spraying unless it is in the upper leaves and growing aggressively. David Hall brought me in some leaves that were affected this morning. After looking at it under the microscope and talking with UGA Plant Disease Diagnostician Jason Brock, I believe it to be Southern Corn Leaf Blight. We are going to keep monitoring it, but I do not believe it will warrant a spray.
