481 - Weed Control Strategy Should Include Soil Applied
Sugarbeet growers again identified weed control as their number one production problem in 2005. Pigweed was named the most serious weed problem 42% of the time, followed by Kochia at 29% and Lambsquarters at 15%. The grower cost benchmarking studies indicate weed control is the second highest cost of production expenditure at $75 to $85 per acre. Prices for Nortron and Ethotron have declined significantly this winter. Maximum weed control is best achieved when Kochia is present or fields have severe weed pressure using soil applied Nortron or Ethotron as a foundation treatment followed by necessary POST applications of herbicide.
Economic Impact of Weed Competition Economic impact of efficacy of weed control based on 2005 grower survey responses and weed competition research is shown in Table 1. Total losses are based on 498,000 planted acres. The data in table one is based on research in 2004 and 2005 by Dr. Larry Smith, U of M and Dr. Alan Dexter’s annual survey.
Table 1. Economic Impact of Weed Competition to ACSC
|Weed Control Rating||% of Acres *||$ Loss/A (++)||Total ACSC Revenue loss|
* - 4% were no response ++ - Based on $40/ton beet payment
Why Do These Losses Occur?
- Post emergence broadleaf herbicides don’t always give excellent weed control.
- Herbicide misapplications
- Herbicide resistant weeds
- Weather problems
- Shift in weed populations
Options to Maximize Weed Control in 2005
Achieving maximum weed control in 2005 may necessitate a return to use of a soil applied herbicide. Research in 2005 by Dr. Dexter achieved nearly 100% control of pigweed and Lambsquarters and 98 to 99% Kochia control with 7.5 pints of Nortron applied PRE or PPI followed by 4 Progress microrates. For best results and to save time and dollars apply these products in a 7 inch band over the row at planting. It’s also possible to use a band sprayer after planting to apply the herbicide in a 7 to 11 inch band.
Benefits of Nortron and Ethotron
- Safest soil applied herbicide for beets in the Red River Valley
- Good to excellent control of resistant Kochia
- Good to excellent pigweed control
- Effective weed control for up to 10 weeks
- Weeds that escape through banded Nortron are pre-conditioned for easier kill
- Eliminates need for a layby herbicide
- MAY reduce the need for one microrate application
- Cost of a 7 inch band estimated to be about $19-24 (dependent on product prices and rates)
Use Guidelines for Nortron and Ethotron
- Heavy previous crop residue may reduce weed control
- 0.5 to 0.75 inches of rain needed to fully activate the herbicide
- Don’t cultivate close to beet rows, this may reduce weed control
- Will control cover crop in the banded area
- Best to rotate to beans or corn after use – carryover damage might occur to wheat after beets if the growing season is very dry
- Can be tank mixed with Roundup at planting time
- Don’t use looped drag chains for incorporation
For More Information
- Contact your agriculturist
- Contact your university specialist
- Contact your crop consultant, chemical dealer or manufacturer
- Refer to the weed control section of the current Sugarbeet Pocket Production Guide
- Refer to the weed control section of the annual Sugarbeet Research and Extension Report