What seems to be becoming another Iowa tradition also started earlier this week in our area.

The last few days have seen a lot of Air Tractors, Ag Cats and other high dollar spray planes in our area applying fungicides. There is some debate as if to spray them or not, and the ICM Crop News site addresses that issue pretty well in several articles. There is a lot of debate about which brand to use, and which fields to apply them to, some of the answers to those questions can also be found on the ICM Crop News site.

There are some great articles there that discuss how to prioritize fields for fungicide apps, for both corn and soybean. As to what product to run, I tend to leave that up to the individual grower and his supplier to decide. A lot of factors go into that decision that are best made locally.

In general, agronomists and researchers agree that not every field needs a fungicide application. Another issue that almost everyone agrees on is that when we do choose to apply fungicides, labeled rates should be used. However, recently I have heard a few reports of half rate recommendations being made. While we understand the economics driving this, there is too much risk involved. Below label rates of fungicides expose us to a much higher chance of the diseases we are trying to control becoming resistant to the fungicides. My understanding is that in Europe, fungicide resistance is a major challenge for crop producers- maybe Dr. Palle Pedersen can comment on that. In addition to the increased risk of fungicide resistance, below label rates are not likely to be as efficacious (there is a big word- I heard Dr. Owen use it one time, thought I’d try it…). What I am getting at is that length of residual, and overall disease control, is likely to be compromised at below label rates.

This time of the year also means watching for western bean cutworm in our corn, soybean aphids in our soybean fields, as well as our more traditional crop pests. Good luck, enjoy scouting in the hot, humid weather- I bet it is tough riding a bike across Iowa in these conditions…

SOURCE: ISU’s Clarke McGrath

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