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Control; It's the Heart of Weed Management

Before any control method can be used, the costs, benefits and environmental impacts must be considered. In controlling weeds, it is best to consider and employ a variety of control methods. It may seem counterintuitive, but once a weed invasion gets too large to completely eradicate, the battlefront should shift to the fringes of a weed invasion rather than where weed densities are highest.

Group of people making a plan

Plan a cost-effective strategy
Because money, time, and labor are limited, the goal is to get the most effective control with the resources available. Most large-scale weed control programs are completed in a series of steps. The area for control should be divided into smaller units to make them more manageable. Then, control should be carried out unit by unit at a rate compatible with economic objectives.



Integrate multiple techniques

  • Mechanical removal includes disking, mowing, and hand pulling.
  • Images showing weed control methods
  • Cultural control efforts include prescribed burning and selective grazing.
  • Biological control is primarily the use of natural plant predators like certain bugs or fungi to control weeds.
  • Herbicides can target certain weeds and minimize harm to desirable plants.
A long-term commitment of at least 3 years is often necessary to deplete the weed seedbank. Changes in management approaches may be necessary to adjust to any unforeseen problems and improve effectiveness. Once the desired level of control has been attained, yearly follow-up is necessary to prevent reinfestation.



Contain the infestation
Containment restricts the spread of large-scale weed infestations. Studies have shown that containing weed infestations is cost effective because it preserves neighboring uninfested rangeland and enhances the success of future control programs. Containing a large-scale infestation requires preventative techniques and control measures on the border of weed infestations to stop the advancing front of weed encroachment.

Treat areas most likely to recover first
Initially, weed control should focus on range sites with existing desirable grasses and the highest potential for recovery. Suppressed grasses have the greatest chance of re-establishing dominance on these sites. Following initial control efforts, treat adjacent areas to minimize re-introduction of the weeds.

Selection and application of weed control techniques in large-scale control programs depends on the specific circumstances for each portion of the management unit. Control techniques used in one area of the management unit may be inappropriate for another.

Images:
-Planning group: Public domain.
-Control techniques:Public domain.

Text references:
-Colorado Natural Areas Program. 2000. Creating an integrated weed management plan: A handbook for owners and managers of lands with natural values. Colorado Natural Areas Program, Colorado State Parks, Colorado Department of Natural Resources; and Division of Plant Industry, Colorado Department of Agriculture. Denver, Colorado. 349 pages.
-DiTomaso, J.M. 2000. Invasive weeds in rangelands: Species, impacts, and management. Weed Science. Vol. 48 No. 2 pp. 255-265.
-Guidelines for coordinated management of noxious weeds: Development of weed management areas. Center for Invasive Plant Management. Available: (http://www.weedcenter.org/management/guidelines/tableofcontents.html 17 October 2006).
-Sheley, R.L. 2004. Rangeland Weed Management. MontGuide fact sheet#199504/Agriculture. Montana State University Extension Service. Boseman, Montana.
-University of Nevada Reno. Cooperative Extension. Fact sheet 96-12. Available:(http://www.unce.unr.edu/publications/FS96/FS9612.pdf 17 October 2006).