ISSUE #355



Unfortunately domestic and worldwide by-products and sugar prices are depressed at this time and may remain low for one to several more years. In spite of this, many growers were successful in raising high quality beets with $40/ton or greater payments in 1998. How ACSC growers can achieve high payment per ton quality beets while maintaining yields will be addressed in each issue of the Ag Notes for 1999.

The growing season environment is critical to your success. However, impact of unfavorable weather can be minimized and advantage taken of favorable weather by careful crop planning. Factors such as rainfall, temperature, hail, frost, wind, soil type and others are beyond control. Variety selection, pesticide use, cultural practice selection and many other production inputs can be controlled. Production of a high quality 1999 beet crop with high revenue per ton and per acre starts with variety selection for next year.

  • Consider high revenue per ton varieties.
  • Don't neglect cercospora leafspot rating -- disease potential appears high for 99.
  • Is an aphanomyces tolerant variety treated with Tachigaren needed to maintain high plant populations.
  • Order enough seed for far seed spacing needed to achieve optimum plant populations.

Based on the statistics and assumptions in the ACSC November 1998 forecast, sugarbeets with an 18.55% sugar content and a 1.53 percent SLM would be worth $40/ton. Producing a beet crop with 350 pounds/ton recoverable sugar is a great challenge. If it had been achieved with the 98 crop, the factories could have produced the same amount of sugar in 20 less campaign days. Twenty less campaign days would be a savings of or a beet payment increase of per ton.

Rhizomania in the RRV

Rhizomania was discovered for the first time in 1997 in two fields near Ada, MN. Rhizomania is a root stunting disease that results in reduced root yield and low sugar content. Typical symptoms include a constricted root with proliferation of lateral roots with fuzzy hair roots. Leaves are usually yellowed and are sometimes narrow and upright. On some leaves there is a distinct yellow veining. Rhizomania is caused by the beet necrotic yellow vein virus (BNYVV). The virus survives many years in the soil and is transmitted to the beet root by the fungus Polymyxa betae. Polymyxa is present in almost all soils where sugarbeets are grown including the Red River Valley. All that was needed for rhizomania to occur in the Valley is for the beet necrotic yellow vein virus to be introduced on soil carrying the fungus and the virus. Any activity that moves soil from rhizomania areas has the potential to infect new beet growing areas. We want growers to know about rhizomania, how it spreads and precautionary methods to prevent yield loss.

How Widespread is the Disease in the RRV?

In 1998, the Agronomy Services Department surveyed fields to determine incidence and severity of the disease. Moorhead agriculturist, Greg Richards and scout Nick Arends coordinated survey efforts. Every beet field within five miles of 1997 positive fields was checked twice for evidence of rhizomania. Suspect fields were evaluated three times. All agriculturists received training in rhizomania identification, then referred other suspicious fields to the survey team.

How Many Fields have Rhizomania and Where are they Located?

A total of 46 fields were sampled and 44 identified as positive for rhizomania. All positive fields were in the Moorhead and Hillsboro districts. Some were nearly 50 miles away from fields with the disease in 1997.

Where/How was the Disease Identified?

Plant and soil samples were sent to Dr. Ben Lockhart at the University of Minnesota, Plant Pathology Department in St. Paul for analysis. Dr. Lockhart is a virologist assisting all three cooperatives with rhizomania problems. His research is partially funded by a grant from the Sugarbeet Research and Education Board of MN and ND using your research checkoff dollars. A standard ELISA diagnostic test, plant grow out in the greenhouse, and election microscopy were all used to confirm disease presence.

Where should a Grower Look for DIsease Symptoms in a Field?

It is favored by warm, wet soil conditions. Early planting associated with these conditions favor infections of seedling beets. Greatest yield losses in Texas, Idaho and southern Minnesota have been associated with early season seedling infection. Replant beets in infected fields may be particularly susceptible to yield loss.

How does the Disease Spread?

Rhizomania is a soil borne root disease. It is not related to rhizoctonia. Anything that moves infected soil can move the disease to a "clean" uninfected field. Soil movement is most likely by wind, water, and tillage equipment. Movement of the disease by tare soil is possible.

Is Rhizomania Causing Yield Loss in Minnesota and North Dakota Fields?

In the RRV in 1998, disease was limited to areas far less than one acre in size in nearly every field. Dr. Charles Rush, Texas A&M, plant pathologist and I visited many RRV fields with rhizomania in 1998. He commented "It is important to realize the disease was not just introduced this year.

Based on the widespread distribution in the Minnesota growing area of the Moorhead and Hillsboro districts it's without detrimental impact on yield and quality now". He

Further stated "cercospora and aphanomyces will have far, far greater economic impact in the near future. Incidence and severity of the disease in southern Minnesota has increased considerably since 1995. Economic yield losses were experienced in some fields in southern Minnesota in 1998.

How is the Disease Controlled or Managed?

  • Surveys to locate infested fields will aid in limiting spread of BNYVV to clean fields.
  • Lengthen crop rotations as much as possible. John Gallian, University of Idaho, sugarbeet specialist recommends at least a four year rotation.
  • Plant early.
  • Use cultural practice that enhances rapid, vigorous seedling growth and canopy development.
  • Improve field drainage to eliminate wet areas most suitable to BNYVV.
  • Avoid spring field compaction that reduces drainage and increases disease risk.
  • Fumigation is very expensive (up to $200/acre or more) -- efficacy is being evaluated in southern Minnesota.
  • Use of soil applied fungicides has been ineffective.
  • Resistant varieties are the best method of disease control.

Are Resistant Varieties Available to ACSC Growers?

Four rhizomania resistant varieties are approved for sale as specialty varieties in 1998. They have been tested in coded variety trails in the RRV. Nearly 30 varieties were evaluated by Mark Bredehoft in SMBSC trials in 1998. Disease severity observed in 1998 would not warrant use of a resistant variety in the RRV at this time.

Sources of More Information on Rhizomania

  • Your Agronomy Services Department agriculturist
  • NDSU Extension Bulletin PP1142
  • U of MN Extension Bulletin BU-7192-S
  • The Research & Education Board web site at
  • University of Minnesota - Dr. Ben Lockhart or Dr. Carol Windels
  • NDSU -- Dr. Art Lamey

The 1999 Research Reporting Session will be held Tuesday, January 12, in the Fargo Holiday Inn, 8:00 a.m. to 5:00 p.m. These are very technical presentations. Contact Eddie Bernhardson at 701-231-8596 or Alan Dexter at 701-231-8131 for more information.