ISSUE #420

420  - Weeds Continue As #1 Grower Production Problem

5-4-02

Weed competition has been rated the most serious threat to sugarbeet production in 20 of the last 25 years in the NDSU/U of MN survey, figure 1.

Figure 1

420.1

Losses From Weed Problems Include:

  • Reductions in yield
  • Reductions in quality
  • Increased production costs
  • More difficulty defoliating the crop
  • Greater difficulty harvesting the crop
  • Storage losses increase from weeds in piles
  • Weed escapes serve as alternate hosts for sugarbeet diseases and insects

Herbicide Resistant Kochia Control:

Use preemerge Ethofumesate as the foundation for effective weed control. Prices of Ethofumesate (Nortron, Etho SC) have decreased by about 40%. Cost of a 7” band is about $24/A and a 3 qt./acre rate in an 11 inch band is less than $36. Etho SC and Nortron are also very effective on Kochia, Redroot Pigweed and many other weeds.

Effective Kochia Control Steps:

  • Thorough preplant tillage
  • Use Preemerge Nortron or Etho SC
  • Plant problem Kochia fields last
  • Use preemerge Roundup or Paraquat
  • Always use Upbeet
  • Use conventional rates of Progress on 0.25 to 0.50 inch diameter or larger Kochia
  • Use effective herbicides in rotational crops
  • Roundup, Liberty, Starane, Authority, Flexstar, Reflex, etc.

Cost of Weed Competition Very High:

One healthy surviving pigweed per three feet of row reduced yield by 30% and revenue per acre by $90. A single pigweed per 10 feet of row competing with the beet crop all season can reduce revenue/acre by $10 to $20, figure 2.

Figure 2

420.2

Microrate Best Management Practices

  • Always include Betanex, Betamix or Progress
  • Always use Upbeet
  • Always use MSO or a basic blend adjuvant
  • Always use Stinger
  • Use a grass herbicide as necessary
  • Start applications 14-21 days after planting
  • Always use 3 applications, 4 if needed
  • Add Nortron or Etho SC to maximize control
  • Increase rates of Betanex, Betamix or Progress as beet size increases
Beet SizeBetanex or Betamix RateProgress Rate
Cotyledon to 4-leaf 8 oz. 5.7 oz.
4-leaf and larger 8-12 oz. 8.6 oz.

Frost and Herbicide Injury:

  • Herbicides applied 12 to 24 hours after a frost caused less sugarbeet injury than when applied the day before a frost.
  • Herbicide and frost injury were greater on small sugarbeets.
  • These results documented in NDSU/U of MN research by Dexter and Mayo.

Always Read and Follow Pesticide Label Directions:

Ethofumesate Plus Microrate:

Adding 4 oz. of Nortron or Etho SC to the first two microrates increased Kochia and Lambsquarters control by 10 to 15% in 2001 NDSU/U of MN research. Cost is only $1.50/acre in an 11 inch band.

Crop Safety Reminder:

Always remember to reduce post emergence rates if applying them over a preemerge herbicide – See pg. 29 in NDSU Pocket Production Guide.