This is the sugar beet report, bringing you the latest information from NDSU throughout the sugar beet growing season. Most of the valley is receiving decent rain, and things are heating up. Ideal conditions for sugar beet and, unfortunately, for Cercospora leaf spot. We're talking with Ashok Chanda, extension sugar beet pathologist with the University of Minnesota and Northwest Research and Outreach Center in Crookston, Minnesota. Ashok, most sugar beet fields are past row closure. Are you seeing much development of cercospora leaf spot?

So, Bruce, I think, you know, we have some beets really planted in the April and then some in the May and then some middle of the May. Right? So we have three generations of beets that we have in the field. But if you especially look at the sugar beet fields in Southern Minnesota, you know, they've been getting a lot of strong storms, which is also causing some damage. There is some wounding. We can actually see some bacterial leaf spots. Sometimes they are just cosmetic. But if the growers are seeing more and more bacterial type leaf spots, you know, they definitely need to think about, you know, the best way to tackle them. But other than that, we're seeing more Cercospora leaf spot developing against in Southern Minnesota, but we're also seeing some disease developing in the Red River Valley here.

What's the best way to manage Cercospora leaf spot?

So the number one thing for managing cercospora leaf spot is, you know, some of the decisions that were already made when they were, planting in terms of, you know, selecting the varieties that are resistant to cercospora leaf spot. But, really, at this time, we are past the row closure. The only thing that can save the sugar beet from cercospora leaf spot is spraying fungicides. When we talk about spraying fungicides, the timing is key. So early is always better because, you know, in terms of disease management, the prevention is better than cure. If we take care of one spore of cercospora right now, that is actually equivalent to 100 spores next week. Again, spraying fungicides timely, which is about ten to fourteen days interval. So you always need to have a contact fungicide like a tin or a b d c tag mixed with the DMI fungicides. Now we call this Triazole fungicides. When we spray this, they just go into the tissues, and then they can actually provide protection from those early germination events of those pores. So you have to have both and then keep the spray intervals tight.

Do CR plus sugar beets need to be managed differently?

So it's been three years that, you know, we have been using CR plus varieties. These are the varieties that have a high tolerance to the cercospora relief spot. Right? I'm saying tolerance, but these are not immune, which means that they can have cercospora leaf spot on them. But what we're observing is that every year, we're seeing earlier earlier development of leaf spot on c r plus, which means the cercospora strains that we have now are adapted to the c r plus varieties. After three years of development on CR plus varieties, I think 2025, we cannot consider CR plus varieties separately, you know, as compared to the susceptible varieties, which means the same fungicide program should be used for CR plus varieties.

What are some important things to consider when using fungicide applications?

So that's a great question. So number one, like I said, timing is key. And number two, rotating different modes of action, so we need to have both contact and systemic fungicides at ten to fourteen days interval. Right? But, again, when we look at the scenario, especially in Southern Minnesota, it's been raining a lot. Right? You only have one day in a week that you can get your spraying done. But, again, they're looking at two to five minutes of rain this week. So if you cannot get the ground rake into the field, you know, call your friends. They can get the aerial application done. And number two, some of the canopies are very strong because the conditions favorable for sugar beet development are also favorable for cercospora leaf spot development. So you need to use at least 20 to 25 gallons per acre so you get actually very good canopy penetration. And if you want to use some aid for deposition, please add that to your tank mix to do that.

Thanks, Ashok. Our guest has been Ashok Chanda, extension sugar beet pathologist with the University of Minnesota and Northwest Research and Outreach Center in Crookston, Minnesota. This is the sugar beet report, bringing you the latest information from NDSU throughout the sugar beet growing season.