lncreased Spent Lime Usage in Southern Minn
Affirmed by University/Co-op Research Results
The spreading of spent lime (more-technically known as Precipitated Calcium Carbonate, or PCC) on upcoming sugarbeet fields has really taken off during the past decade among Upper Midwest beet growers. Along with increasing pH and influencing the soil nutrients, the spent lime has been demonstrated to reduce the impact of Aphanomyces and Rhizoctonia root rot in infested fields.
Idaho USDA-ARS Research Aids in Work to Rein in Rhizomania, Curly Top
By Ann Perry*
The whole point of growing sugarbeets is to produce sugar. But once the beets are harvested and stored for processing, they slowly start to decay, which lowers their sucrose levels.
Rhizoctonia root rot is a serious disease problem in several sugarbeet-growing regions, with the result sometimes being dramatic — and expensive — reductions in tonnage and quality. Low levels of infection can easily cause yield losses in excess of a ton per acre, while high infection levels can cut yields by more than 10 tons per acre. The quality of surviving beets can also be impacted, sometimes resulting in significant losses in recoverable sugar.
Though sugarbeet producers in western states have dealt with significant levels of Rhizoctonia crown and root rot for many years, the disease’s development as a serious problem in the Red River Valley and Southern Minnesota growing areas is a more-recent phenomenon.
A key factor in Rhizoctonia’s “Upper Midwest expansion” over the past several years is cropping patterns. There now are fewer wheat and barley fields (nonhost crops) and more corn, soybean and edible bean fields (all host crops). That has translated into more disease inoculum present in soils to threaten sugarbeet crops that follow corn or beans. “We think the number-one driver [behind the increased incidence and severity of Rhizoctonia] — if talking about the whole Red River Valley — is soybeans,” says Allan Cattanach, general agronomist for American Crystal Sugar Company. “Whereas corn and soybeans together probably make it worse in Southern Minn, Minn-Dak and the southern end of the Crystal growing area.”
Michigan Sugar Company has a goal to improve beet quality by increasing the co-op’s average sugar content to 19%. This goal is achievable, but it will take increased management and use of higher sugar varieties.
Many of our new varieties have a high tonnage and sugar potential; but several likewise are very susceptible to Cercospora leafspot and Rhizoctonia. Left unchecked, both diseases can greatly affect yield and quality. By using the BeetCast leafspot prediction model and appropriate fungicides, growers are doing an excellent job of minimizing the impact of Cercospora leafspot. While Rhizoctonia is more difficult to manage, we also have made great strides in reducing its effect on yield and quality