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“Sugarbeet Report” presented by NDSU Extension, features growing tips from NDSU sugar beet specialists and researchers.
Bruce Sundeen
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 adequate rain, but now things are heating up. How does this affect the management of cercospora leaf spot in sugar beet? 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, are you seeing much development of Cercospora leaf spot in sugar beet fields?
Ashok Chanda
So we started season with, kind of on the bit earlier this year, and, I know we started season with, kind of on the cooler side, but finally, we are having the heat units, and we caught up with the growing degree days as well. So most of the sugar beets are actually have closed the rows or just about to close rows. So compared to previous seasons, we are a little bit slow in terms of disease development. Now we are seeing a few spots, in the fields that are already closed rows. And then, you know, we always see this cast release part first in the south, and then gradually we see more in the northern part of the valley. If you're following doctor White's lab results from USDARS in Fargo, we know that there are more and more samples that are positive for cercospora DNA in the leaf tissues.
Bruce Sundeen
What's the best way to manage cercospora leaf spot?
Ashok Chanda
So really, you know, when it comes down to use of a, you know, strong variety with the genetic resistance to cercospora, we call this CR plus varieties. I know at least half of the growers are interested in growing these varieties and then others are still depending on their traditional varieties with a little bit more susceptibility to cercospora. As long as you keep on top of your fungicide applications, you know, you can do a pretty good job of having a very good crop. Number 2, crop rotation is also very good. You know, as long as you keep 3 to 4 year rotation with the beets and then try to have this beets a little bit away from the last year, sugar beet fields. That way you're not moving that inoculum from the previous seasons, you know, into the field right away. But, depending on fungicides on top of genetic resistance is very important for managing cercospora leaf spot.
Bruce Sundeen
What are some things to consider when it comes to fungicide applications?
Ashok Chanda
So when we're talking about fungicide applications, right, number 1, like the timing of the applications. Now the fields that closed rows, I think, you know, yesterday was the day to apply the 1st application. And for the fields that are just closing rows, you know, this is the best time to get your first application for cicuspral leaf spot. Right? So follow the recommendations from the co ops. You know, typically, you start with the DMI fungicide and also a broad spectrum fungicides such as EPDC, which is, you know, mancozeb. Then you can come back with a 10 antitoxin in the second application. You know, if you're only relying on a EPDC like a mancozeb for the first application, and if you have a couple of rainy events, you know, now we have to really shorten the interval for your application. Number 2, spray coverage. You know, try to have at least, you know, 17 to 20 gallons per acre because we have really, like, huge canopies right now. So make sure that everything is covered properly with the fungicide. Number 3, like, no different class of chemistries. You know, you cannot use the same class of chemistry again and again, so just make sure we rotate the chemistries.
Bruce Sundeen
Are you seeing signs of root rot diseases?
Ashok Chanda
So, Bruce, I think, again, in terms of root rots, there are some reports of fusarium that's showing up in the, you know, Moorhead factor districts. You know, it's bound to happen, especially if you have a field with Fusarium history. But if you don't know what's the rating for the variety that you planted in the particular field, typically, if you see half leaf yellowing, you know, that's most of the time where it's fusarium, but to make sure that next time you plant beets, select a tolerant variety. And dumps of rhizoctonia root rot, I know with the heat that we have right now, I know some of the fields with the higher rhizoctonia. Let me show some root rot. If you're in doubt, always bring the samples to our Northwest Region Outreach Center, Sugar Beet pathology lab. We can help with diagnosis.Not only the root diseases, but you can also suspected, you know, the leaf spots. We can help you identify what it is.
Bruce Sundeen
Ashok, do you have any closing comments?
Ashok Chanda
We have a very good potential for crop this year in ostracospora leaf spot. Once it established in the canopy, it's just a matter of time. So just, you know, try to stick with the spray programs. Especially, even if you have CR plus varieties, you know, some of the first applications are very important. Then it gives you a little bit of freedom when you go to the spray 3 and then 4. You can have, like, at least, you know, 3 weeks in a well between those sprays. But if it is a traditional variety, you have to be on top of the program.
Bruce Sundeen
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.