ISSUE #544

544 - Variety Selection Critical Connection to Disease Management

9-23-10

Root disease incidence and severity have increased greatly in the last 15 years for Aphanomyces, Rhizomania, Rhizoctonia and Fusarium. Rhizomania was first identified in 1997 and by 2005 was present in nearly every RRV field. Fusarium was first identified about 1996 and is severe in the Moorhead district. It has spread to all other factory districts at this time. Aphanomyces and Rhizoctonia severity is increasing too.

Factors Contributing to Disease Severity Increases

  • Large rotational acreages planted to Rhizoctonia susceptible crops
  • Short crop rotations
  • Lack of highly resistant varieties
  • Poor field drainage
  • Prolonged duration of wet weather since 1993

Disease Severity Maps Available

American Crystal agriculturists have rated each township in our growing area for severity of each of the four major root rot diseases. Diseases were rated as none, slight, moderate or severe. Figure 1 is a map of Fusarium severity in the southern RRV. Figure 2 is a map of Rhizoctonia severity in the northern RRV.

544.1

Contact Your Agriculturist for variety performance experiences in your local area and disease rating maps.

Variety Root Rot Ratings Available

Crystal Beet Seed has categorized varietal disease resistance based on disease nursery evaluations. Figure 3 is an example of this information from disease rating data.

544.2(click above table to enlarge)

Using Disease and Variety Information

Combining the information available from disease maps and variety disease rating data should result in best variety selection and more on-farm profit.

  • Determine township field is in
  • Determine disease risk profile for that township
  • Choose a variety with the best combination of disease resistance and revenue per acre for each field.

Choose varieties coded green for moderate to severe disease, black coded ratings for slight to moderate disease, and red coded disease ratings if no disease is present in the field.

Other Very Important Variety Selection Criteria

  • Revenue per acre
  • Recoverable sugar per acre
  • Revenue per ton
  • Recoverable sugar per ton
  • Variety emergence ability
  • Variety vigor
  • Harvestability
  • Available seed treatments

Zone Fertility Management has increased profit by more than $50 per acre compared to conventional soil sampling and fertilizer application.

Insecticide for 2011

Be sure to check with your seed supplier regarding insecticide treatment availability or use granular insecticide for root maggot management in 2011.