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“Sugarbeet Report” presented by NDSU Extension, features growing tips from NDSU sugar beet specialists and researchers.
This is the Sugar Beet Report bringing you the latest information from NDSU throughout the Sugar Beet growing season. Most of the Red River Valley is receiving adequate rain, and temperatures are up. So how do these conditions affect cercospora leaf spot in sugar beet? We're talking with Eric Branch, NDSU and University of Minnesota Extension Sugar Beet Specialist. Eric, this season, sugar beet beet growers planted early and had plenty of rain. How does this combination affect cercospora leaf spot?
Eric Branch:I like how you mentioned it. We had plenty of rain. That's true. It's now hot and dry and it's hot and drier depending on where you are. You know, it's drier, but lots of our fields are still getting plenty of moisture. And of course, Cercospora leaf spot thrives on moisture, particularly that relative humidity within the canopy, as well as water, whether that's dew or rain on the leaves, also promotes spore germination and infection. So, this is the time of year where we've got these temperatures. We are seeing, an increased risk of cercospora leaf spot based on the conditions and that's reflected in the NDAWN DIV calculation, on the NDAWN website where we can see the trend in DIVs cranking up and up and up into that moderate and severe risk for a certain cost per leaf spot all up and down the valley, actually. And that's really been noticeable this year, especially since we had somewhat of a cooler June, especially evenings in June were a little bit cooler and we've seen cercospora leaf spot this year slower to develop and whether that's purely environmental or be hopeful of great management from the growers in terms of both sugar beet genetics being used, as well as, getting timely sprays in. And taken together, we've seen a very moderate start to the cercospora season. But, of course, nothing good can last forever. So we hit this time in at the end of July, early August, and humidity's up and rainfall is still coming. Temperatures are up, so we do expect to see increasing onset of sugar beet cercospora.
Bruce Sundeen:What about treatment right now? Do you have some options?
Eric Branch:Yeah, absolutely. And of course, right now, the best treatment for cercospora during the season is timely and choosing the right product, and applying it at the right time. But I know we plant pathologists like to say that. We do it because we've got the data. It's worked in previous years. There's been great work from not just NDSU, but also the University of Minnesota and USDA and the co ops, all coming up with very similar recommendations now for early sprays, as well as really continued calendar based sprays that have been very effective in managing leaf spot throughout the past few years. We hope to see that this year as well.
Bruce Sundeen:How pervasive is cercospora leaf spot compared to other years?
Eric Branch:Compared to previous years, I would say cercospora leaf spot is a little bit delayed perhaps but we've had several seasons here in the valley of fairly light cercospora. So it remains to be seen how August is gonna go for us.
Bruce Sundeen:What's going on with some other diseases?
Eric Branch:We are now kind of at that time period, especially with the recent rains. I know some of my own fields got as much as 2 inches in the last week and a half over several rain events. My research plots, that is, root diseases are still active at that point. Rhosoctonia, in particular, I'm seeing and and we're hearing about some patches of Rhosoctonia where environmental conditions and just how it's located in the field, we have a a hot spot. Seed treatment may have been used, and then an infra or post emergent may have been used. But sometimes, that's just not enough, especially in such a wet year, maybe in a low spot in the field, and we see disease symptoms developing. At this late in the season, it's really not much we can do to protect the plants at that point. Even plants that aren't really wilty yet and may look healthy, of course, may be suffering, may be affected by Rhosoctonia as well. And that's just kind of a situation where we look to corroboration and and thinking ahead to the opportunities for future years as well.
Bruce Sundeen:Eric, tell us about your upcoming plot tour on August 29th.
Eric Branch:You know, I can thank again my cooperators at NDSU for great plot tours in Saint Thomas and Prosper and now we are looking ahead to Fox Hill, Minnesota and that is a plant pathology research site. We have some real interesting experiments in terms of fungicide efficacy and application timing and, we hope to have some crispy plots for all of us to see some good results. Hopefully, that do lead to providing good data for recommendations on actions we can take against sugar beet diseases.
Bruce Sundeen:Thanks, Eric. Our guest has been Eric Branch, NDSU and University of Minnesota Extension Sugar Beet Specialist. This is the Sugar Beet Report, bringing you the latest information from NDSU throughout the sugar beet growing season.