New technology delivers resistance against cercospora — the 'No. 1 production problem' in sugarbeets

By Mikkel Pates

Sugarbeet growers have a new weapon against their No. 1 nemesis in recent years, the fungus cercospora.

New sugarbeet seed varieties resistant to cercospora leaf spot disease were commercially available for growers to plant in southern North Dakota and Minnesota in 2021. The improved varieties will save tens of millions of dollars in spray and processing costs and could save hundreds of millions in crop losses.

Mohamed Khan, a professor and Extension sugarbeet specialist for the University of Minnesota and North Dakota State Unviersity, said he expects to see most farmers to adopt the technology in the next three years. He thinks its use in the next two or three years will extend to Michigan, Montana, Nebraska, Colorado and Wyoming.

Sugarbeets are the most prominent specialty crops from southern Minnesota to the Canadian border through the Red River Valley, accounting for some $5 billion in economic activity. But that activity can be hurt by cercospora, which turns green leaves brown, shutting down yield potential.

The new CR+ (cercospora resistance plus performance), from KWS Saat, parent company for Betaseed, commercialized seed for some growers in southern Red River Valley of North Dakota and into southern Minnesota.

German-based genetics company KWS Saat in its website on the topic says about two-thirds of global sugarbeet acreage has a moderate to high cercospora pressure. Cercospora is the most destructive leaf disease of sugarbeets, sometimes cutting crop yield by 50% in some places, the company says on its website.

Khan said the new technology will prolong the usefulness of other fungicide treatment.

“It’s a real game-changer,” he said, describing the technology in a private tour of his cercospora research plots near Foxhome, Minn., about an hour east of Fargo, N.D. The site has a plot tour on Aug. 24, 2021.

Mike Metzger, vice president of agriculture for Minn-Dak Farmers Cooperative at Wahpeton, N.D., has had the new CR+ varieties in his company’s research plots for two years. He describes cercospora as the co-op’s “No. 1 production problem.”

Metzger said that 60% of seed planted by Minn-Dak Farmers Cooperative at Wahpeton this year were the improved cercospora-resistant sugarbeet varieties. Khan said about 15% of the crop for Southern Minnesota at Renville also also are the new varieties.

All of Minn-Dak’s members this year were offered an opportunity to buy the new seed, and Metzger estimates that 80% to 85% did. The new seed came at about a $40 per acre cost above the typical seed price, which ranges from $200 to $250 an acre.

“It’s going to offset three sprays,” which Metzger and Khan say is at about $25 to $30 per spray.

Metzger likened the new variety impact to the to “herd immunity” when it comes to COVID-19. Going to resistant varieties could drastically reduce the amount of fungus over a two-or three-year period.

“We don’t have to worry about that massive cercospora cloud hanging over our head. It gives us a chance to take a breath, hit the reset button,” he said.

Khan said the new cercospora-tolerant varieties appear to have tonnage yield comparable to approved sensitive varieties. The sugar concentration may be a little lower.

"But overall, the recoverable sucrose is as good as the other varieties we’ve had,” he said.

He said other seed companies (Crystal Beet Seeds, SESVanderHave, Hilleshog and Maribo) also are working toward commercializing resistant varieties.

While the cercospora-resistant varieties so far have come through conventional breeding, Khan said the industry is looking at developing other traits through genetic modification. Some on the horizon include triple-stack resistance to glyphosate (Roundup) glufosinate (Liberty) and dicamba perhaps in 2025 or 2026. The only sugarbeet GMOs now approved for use are for Roundup (glyphosate) resistance.

Read the full article at Agweek.