Notes from NDSU extension sugarbeet specialist, Mohamed Khan, on the state of Cercospora Leaf Spot
Last year, Cercospora leaf spot throttled sugarbeet regions across the upper Midwest. Forecasts anticipated Cercospora severity to be equally, if not worse, in 2017. However, things aren’t too terrible in North Dakota and Minnesota as the calendar shifts from July to August.
Initial widespread symptoms started to appear around the middle of July, which triggered fungicide applications across the region.
“In the southern regions, they got started a little earlier than growers up north,” said Mohamed Khan, extension sugarbeet specialist for North Dakota State University and University of Minnesota. “They have also seen more rainfall so they will need to continue to be on time with their applications.”
Khan says the weather has played a major factor in the development of Cercospora this season.
“We had a very long dry period, which helped out alot with Cercospora,” he said. “It also set back to crop a bit too. As of now, I would say disease pressure is low, which is good. However, inoculum pressure is still high so if conditions turn wet, growers have to stay on guard.”
Fungicide resistance was also a big concern entering the growing season, but so far it hasn’t been an issue.
“We haven’t seen any issues out in the fields yet, so we recommend that growers continue to use mixtures of fungicides. They should also use a broad spectrum fungicide with their single site mode of action. Growers should shorten their intervals if it rains shortly after an application. They should keep scouting their fields so they can keep an eye on things and know when to make the decision to shorten their intervals.”
Editor & General Manager of The Sugarbeet Grower