ISSUE #433

433 - Back To The Basics

2-18-03

The NDSU/U of MN sugarbeet grower seminars have just recently been completed. Dr. Alan Dexter again provides an excellent look back at the problems of 2002. He then provided a roadmap of strategies to follow for better weed control success in 2003. This issue of "Ag Notes" will provide highlights of Dr. Dexter's presentation

Weeds continue to be the worst production problem and need to be a management focus in 2003.

NDSU Sugarbeet Grower Survey

Worst Production Problem2002 2001 2000 
  % of Responses  
Weeds  53  52  48 
Emergence/Stand  19  10 
Rhizoctonia/Aphanomyces  16  18 

Pigweed species, waterhemp, kochia, lambsquarter, and smartweed were the most serious problems in 2003. Weed control success is dependent on exact diagnosis of the weeds present in each field.

Annual Sugarbeet Grower Survey

Worst Weed2002 2001 2000 
 % of Responses   
Pigweed spp.  44  43  18 
Waterhemp 
Kochia  26  32  43 
C. Lambsquarters  14  10  19 
Smartweed spp. 

NDSU/U of MN Weed Control Strategies For 2003:

  1. Prevent weed seed production in all rotational crops:

    • Kochia seed germination is reduced 98% after 2 years in the soil
    • Redroot pigweed germination is reduced 73% after 2 years in the soil.
    • Successful use of Roundup ready crops.

      • Always add AMS at 8.5 lb./100 gal. of spray.
      • Use 3 to 10 gpa total spray water volume.
      • Follow adjuvant requirements.
      • Morning dew on the plants reduces Roundup control.
  2. Kill all weeds just before or just after seeding:

    • Complete coverage tillage.
    • Use pre-emerge Roundup.
    • Combination of tillage and Roundup.

    Roundup was definitely under used at only 6% of 2002 acres. Over 75% of growers rated its use good or excellent in 2002.

  3. Soil Applied Herbicides:

    Growers reported excellent or good results 78% of the time in 2002 with Nortron. Nortron or its ethofumesate containing generic products give very good Kochia and Pigweed control. It should definitely be considered in fields with high weed populations. See Ag Notes issue #431 from January 13, 2003 for an extensive discussion on proper use of Nortron, Etho SC or Ethotron (all ethofumesate containing products).

  4. Good Sugarbeet Populations:

    Establishing 180-190 plants per 100' of row maximizes crop competition with weeds and achieves maximum recoverable sugar per acre.

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  5. Post Emergence Herbicide Use:

    • Grower satisfaction is still greater with microrate (M-R) than with conventional rates (C-R).
    • Betanex use is decreasing in the M-R.
    • Progress use is increasing in the M-R.
    • Progress conventional rates used 3X increased Kochia control by 26% over Progress M-R used 4X.
    • Betanex M-R used 4X increased pigweed control by 6% over 3 applications of Progress in C-R.
    • M-R gave 100% grass control while C-R's gave only 72-86% grass control.
    • M-R and C-R each gave 98% Lambsquarter control.
    • Increasing Upbeet in M-R from 1/8 oz. to ½ oz. will often increase Pigweed control by up to 15%
    • Never apply M-R without Stinger.
  6. Lay-By Herbicides:

    • 26% of 2002 acres were treated with Outlook.
    • 51% of growers rated Outlook weed control good or excellent in 2002.
    • Apply Outlook on 4 true leaf or larger beets to minimize crop injury.
    • Outlook with Betamix M-R increased pigweed control by 10-23% over the Betamix M-R alone.
    • Layby Treflan was used on 4% of 2002 acres.
    • 69% of Treflan layby use was rated good to excellent.
    • Potential exists for extreme injury from layby Treflan.
  7. Cultivation, Harrow, Rotary Hoe:

    Use mechanical weed control options when appropriate. Use of rotary hoes and harrowing dropped by about 1/3 in 2002 while hand labor use increased by about 40%. Were excessive late season weeds in 2002 due to less use of mechanical weed control? Row crop cultivations have dropped from 3.2 per field in 1992 to only 1.9 in 2002.

    • Don't row crop cultivate unless weeds are present.
    • Late season cultivation near row closure increases risk of Rhizoctonia root and rot.
    • Cultivation may cause new weeds to germinate.

     Annual Sugarbeet Growers Survey

     2002 2001 
     % of Acres  
    Rotary Hoe/Harrow  42  63 
    Hand Weeded  32  23 
    Row - Crop Cultivation  98  99 

     

  8. Details - Attention To Details:

    • Calibrate sprayers carefully.
    • Calculate herbicide rates meticulously.
    • Set nozzle height accurately.
    • Apply all herbicides timely.
    • Have no preconceptions about how many post applications will be necessary. (Use pesticides according to labels).
    • Use correct nozzles.
    • Use correct screens.
    • Use label required spray volumes.

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  9. Incremental Improvements in Weed Control: 

    • Increase Betanex, Betamex and Progress in M-R after beets have 4 leaves.
    • Add Nortron to the M-R.

      • 4 oz. twice with Progress.
      • 4 oz. three times with Betanex and Betamex.

    • Broadcast rather than band

      • Advantages - easier, faster, less wind effect.
      • Disadvantage - cost.

    • Use conventional rates (C-R) versus M-R on large or difficult to control weeds.

      • Can't add grass herbicide and oil.
      • Must spray in late afternoon or evening.

    • Use ENOUGH, PROVEN high quality adjuvant.

      • 1.5% V/V or
      • A minimum of 1 pt./A and a maximum of 2 pt./A
         
    • Z64 Adjuvant Use

      • Only after beets have 4 true leaves.
      • Use for TOUGH weed problems.
      • Label suggests 2% V/V.

    • Increase Stinger in M-R or C-R for tough weeds i.e. Lanceleaf Sage.

    For further advice on Sugarbeet Weed Control.

    • Contact your agriculturist.
    • Call NDSU or U of MN specialists.
    • Contact your herbicide supplier.
    • See the 2003 Sugarbeet Pocket Guide.
    • Review Dr. Dexter's recommendations and research in the 2002 Sugarbeet Research and Extension Reports, pages 3-87.

A very special thanks to Dr. Alan Dexter for extensive use of his grower seminar presentation data for this Ag Notes.