Fungicide seed treatments for wheat
(Note: The following article is a slightly edited transcript of a short K-State Research and Extension YouTube video produced by Dan Donnert, KSRE videographer. The link to this video is: https://youtu.be/SlaIuMAK53Q – Steve Watson, Agronomy eUpdate Editor)
During the last decade or so we saw a little higher commodity prices, and that stimulated some interest in fungicide seed treatments. As commodity prices have gone down again, people are starting to question whether they really need to do this or not. If you’re not interested in using a fungicide seed treatment on all your wheat, then I would set priorities.
For grain production, one of the higher priorities would be wheat that you’re planning to bring onto your farm as new varieties that you’ll be saving for your own seed.
There are a number of different seed-borne diseases that we might be concerned about. Some of them are just seed-borne, while some may also have a very loose association with soil-borne factors. One such disease is common bunt, which is sometimes called stinking smut because of the strong fishy odor that fungus is able to produce on contaminated grain. Another one might be loose smut. And last year we had flag smut, a disease that re-emerged after a long break of more than 30 years.
All three of those diseases would be primarily seed-borne only diseases and targets for a fungicide seed treatment.
We might also consider fungicide seed treatments for controlling diseases like Fusarium. This disease, which can be seed-borne and come in on seed lots that were infected by Fusarium head blight in the previous year. The seed-borne phase of the Fusarium fungus can affect germination of the seed lot. It can also cause damping off or seedling blight type of diseases in which the seedlings contract the disease and collapse and die before they even emerge in many cases.
Figure 1. Common bunt, or stinking smut, in wheat. Photo by Erick DeWolf, K-State Research and Extension.
Figure 2. Loose smut in wheat. Photo by Erick DeWolf, K-State Research and Extension.
Figure 3. Flag smut in wheat. Photo courtesy of Erick DeWolf, K-State Research and Extension.
Figure 4. Fusarium head blight (scab) in wheat. Photo by Erick DeWolf, K-State Research and Extension.
Most of the fungicide seed treatments marketed widely in the state now include one or more active ingredients that are going to give a fairly broad spectrum of control, including the smut diseases – loose smut and flag smut, quite easily. Where we see some differences is in the control of seed-borne Fusarium or some of those other more difficult-to-control fungi.
It’s going to be a balance for producers to decide, what are the priority fields and what are the costs? These seed-borne diseases can cause a lot of problems for us, so if you look at it in terms of insurance, this is a pretty low-cost practice wheat producers can do to protect against the potential losses they could experience.
Erick DeWolf, Extension Plant Pathology