Weed Control for sugarbeet production
From Sugarbeet Production Guide (UNL Extension Circular 156), Chapter 10, Weed Control
Weeds have a tremendous impact on sugarbeet root yield, especially those that become taller than the crop. They will cause greater yield loss than weeds that do not overtop the crop canopy. Some examples:
Yield reduction caused by weeds (density of 6 plants/100 sq. ft.)
Time of emergence has a significant impact on competitive ability. Weeds emerging with the crop cause greater yield losses than weeds emerging after the crop.
Planning a Weed Management Program
Factors such as weed species, cover crop, preplant tillage, crop rotation, crop cultivar, row spacing, fertility program, cultivation, and herbicides all need to be integrated to develop an effective weed control strategy.
- Accurate weed identification should be the first step, and is important for effective and economical decisions.
- Mapping weed infestations in a field can aid weed management decisions. Scattered patches and individual weeds can be spot-treated with a herbicide, rogued or cultivated.
- Tillage associated with seedbed preparations has a major impact on weed spectrum and population.
- Herbicides can be applied before planting and crop emergence to control weeds as they germinate and emerge with the crop.
- Field scouting immediately after the crop begins to emerge is important to identify weeds and provide the information necessary to choose a postemergence herbicide program that matches the weed spectrum.
- Six weeks after emergence, sugarbeet leaves should be starting to cover the spaces between plants, suppressing further weed growth. Several cultural practices such as optimum plant arrangement, narrow rows, higher plant populations, proper fertilization and selection of cultivars with good disease tolerance, further favor the crop by maximizing shading and hastening canopy closure.
Roundup Ready Sugarbeet and Herbicide Resistance
A large percentage of growers in the Western Sugar Cooperative growing area have switched to Roundup Ready sugarbeet. The use of Roundup for postemergence weed control in sugarbeet should dramatically improve the growers' ability to manage weeds. This has been the case for soybean, corn, and cotton growers in other sections of the U.S. As we move to western Nebraska the predominant use of Roundup has been in corn with some growers continuously utilizing only Roundup for weed control for several years. With 130 million acres of corn and soybeans treated with Roundup in the U.S. in 2008, it is not surprising that weed shifts have occurred and some weed species have developed tolerance to Roundup.
Once growers have switched to a Roundup Ready crop they usually do not want to switch back, but instead want to continue to utilize Roundup, even if tolerant weeds have developed. To address weed tolerance, growers have supplemented Roundup by applying a pre-emergence herbicide at planting followed by Roundup postemergence, tank mixing another postemergence herbicide with Roundup, or rotating a Roundup Ready crop with a non-Roundup-resistant crop. Many growers in the Western Sugar growing region have used Roundup Ready crops sparingly, so initially there should be very few problems with Roundup performance. But Repeated exposure of a weed population to a herbicide may result in a rapid buildup of weed resistance to that herbicide mode of action.
Strategies to minimize herbicide resistant weeds:
- Use herbicides only when necessary.
- Rotate herbicides with different modes of action in consecutive years.
- Apply herbicides as tank-mixes or use sequential treatments that contain multiple modes of action.
- Rotate crops with different life cycles, such as winter annual crops (winter wheat), perennial crops (alfalfa) and summer annual crops (corn or dry bean).
- Combine mechanical and chemical weed control practices.
- Scout fields regularly to identify weeds that escape herbicide treatments.
Recommended Publications on Weed Management
- Guide to Weed Management in Nebraska, EC130 Research results and recommendations on weed management in Nebraska crop production (PDF format, 204 pages). A print edition of this Extension circular is available at Nebraska extension offices or can be ordered.
- The Montana, Utah and Wyoming Weed Management Handbook, Publication No. B442. View the entire publication here (PDF file, 288 pages, 5.1 MB). View the chapter on sugarbeets here (PDF file, 10 pages, 64.6 KB) Printed copies available from the University of Wyoming Resource Center, Box 3313, Laramie, WY 82071; Phone 307-766-2115. Cost is $10, including shipping and handling.
- Colorado Weed Management Guide, XCM205, available from Cooperative Extension Resource Center, 115 General Services building, Colorado State University, Fort Collins, CO 80523-4061. Phone 877-692-9358. Cost is $12, including shipping and handling. Can be ordered on-line; click here.
Original article in Production Guide written by Robert G. Wilson, Stephen D. Miller, and Scott J. Nissen
The complete Weed Control section of the Extension Publication – Sugarbeet Production Guide, EC156, is available on-line (PDF 987KB, 14 pages). This chapter includes:
- Weed identification photos
- Herbicide charts - time of application, percent weed control, crop safety
- Photos of herbicide effects on crops
data from the
NOTE: all links are PDF files.
- Tank Mixtures of Outlook or Nortron in Combination with Roundup for Late-Season Weed Control in Sugarbeets
- Incorporating Roundup Ready® Sugarbeets into a Sustainable Weed Control Program at Scottsbluff, NE, during the 2008 Growing Season.
- Roundup Timing and Tank Mixtures with Roundup WeatherMax Over-the-Top of Roundup Ready® Sugarbeets
- When and What Herbicides to Apply for Layby Weed Control in Sugarbeets during the 2008 Growing Season
- Timing of Weed Removal in Roundup Ready Sugarbeets at Scottsbluff, NE, during the 2008 Growing Season
- Influence of Winfield Solutions Adjuvants on Roundup WeatherMax and Half-Rate Herbicide Programs in Sugarbeets in 2008
- Sequence Crop Tolerance and Efficacy in Roundup Ready Sugarbeets at Scottsbluff, NE, during the 2008 Growing Season
- Weed and Disease Management in Roundup Ready Sugarbeets