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
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.”