This is the sugar beet report, bringing you the latest information from NDSU throughout the sugar beet growing season. Even this late in the growing season, Cercospora leaf spot is hanging around. Providing some advice is Ashok Chanda, extension sugar beet pathologist with the University of Minnesota and Northwest Research and Outreach Center in Crookston, Minnesota. Ashok, we're already in the second week of prepile. What's on your sugar beet disease radar?

Yes, Bruce. I think the season is, like, you know, flying by. This is also some sort of good news. And anytime we start really early in August, that means that, you know, we are actually looking at a pretty good sugar beet crop. So the conditions are kinda perfect for beet growth. But on the flip side, when the conditions are perfect for sugar beets, they're also very conducive for some of the sugar beet diseases. They like exact same moisture and temperature, you know, for their growth and survival. So we are seeing, you know, still some root rots, you know, some rhizoctonia root rot and some fields, which are getting some repeated rainfall. And then, you know, moist conditions, we are seeing some ephememisis root rot in some fields. The biggest problem that we have around this time of the year, every year, is actually cercospora leaf spot. The canopy is full, the heat, and then the moisture, the humidity, it's all very favorable for cercospora leaf spot development. We had some big years in the past few years, like 2016 and 2020, again, 2023. So anytime we had this big disease years, you know, the inoculum kind of, you know, gets carried over to the next years, it causes the disease this year.

What are the best practices to manage cercaris relief spot?

So we have two main tools for managing cercospora leaf spot. You know, number one, in terms of the sugar beet varieties, you know, the traditional varieties are more or less susceptible for cercospora leaf spot. And the new generation of varieties, we call them CR plus. They have really good resistance to cercospora leaf spot, so the growers are planting both of them. On top of that, using fungicides is really critical in managing, leaf spot disease. So there are three things that the growers have to keep in mind. Number one, using different chemistries or modes of action. They have to rotate different modes of action. And number two, the spray intervals. Now, typically, we have to time our sprays between ten to fourteen days interval. It's more or less the time it takes for Cercospora veticular to finish its life cycle, you know, about seven to ten days. So every ten days, it's making these new spores. So that's when, you know, when you're applying this fungicide, so they're actually trying to reduce the inoculum. And the third one is actually using appropriate spray volume. You know, most of the fields need at least 20 gallons per acre so that, you know, the canopy is very, very well distributed with the fungicides that we are applying. Because when we're applying these fungicides, we're actually seeing a systemic fungicide with the contact fungicide, for example, like MancoZep, which is EBDC. It's purely contact. You know, the number of spores that come in contact with this fungicide, you know, they get deactivated. And then the systemic fungicides, once we apply, takes up to twenty four hours for them to get distributed in the leaf tissues, and they actually offer protection from those early infection in the tissues. So that's why we need to use both of them in almost every fungicide application.

Ashok, what about working with fungicides? You see rain in the forecast. What can you do?

Yeah. I think another big theme that we have this year is, problems with rain. I think in some form or shape, I think, you know, we're getting some rain every day. Most fungicide applications have a contact and a systemic fungicide. I know they're built into the spray. If you apply, let's say, only EBDC, and then if you get, like, one to two inches of rain next day, so, you know, more than 50% of the product is gonna get washed off from the leaf surface. But if you have a contact and systemic fungicide that's built into a spray program, you know, you can take that risk, then you're gonna get benefit from that systemic fungicide. But if you definitely see some rain in forecast in the next forty eight hours, I would say at least, you know, you can wait until the rain is done. But sometimes the problem is if you get two inches of rain, you'll be out of the field for, you know, next three to four days. We have to really assess the amount of disease that you're seeing in the field. You know? If you're seeing, like, low category, you're only seeing few spots, you know, really, you can wait until after the rain. But your field is already at risk for the disease, and then, you know, you wanna take the chance and then get your application here, and that means that, you know, applying only ten days after the last application, the disease at it's a critical stage that you don't want to wait too long.

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.