General Weed Management Information

Controlling undesirable plants on pasture and rangeland is an important part of an overall range management program. Undesirable plants use space, moisture, and nutrients that could be put to better use producing forage for grazing animals and wildlife. Poisonous plants are an additional threat to animal health and productivity.

Weed and brush control are not in themselves range management, but are merely tools available to the manager. Long-term control of undesirable plants usually requires more intensive management. In most cases, undesirable plants are able to proliferate as a result of fire, poor grazing management, or other disturbances that degrade pasture and rangeland. It is usually futile to try to control undesirable plants without improving management to reduce or remove these underlying stressors.

Other methods: Methods that have a definite place in range management are: chemical, roto-beating, plowing, disking, railing, chaining, burning, reseeding, and changes in grazing schedules. There are specific sites and reasons for use of these controls. Each is effective if used properly. Well planned combinations of control methods applied in an integrated management system are more effective than any single method alone. In designing a management plan, obtain as much specific, locally relevant expert knowledge as possible. Ideally, consult a range of experts with different perspectives and combine input to develop a strategy that will work for conditions and management objectives of the particular land unit in question.

Safety and toxicity hazard: The toxicity of chemicals used in range weed control is generally very low. No evidence of direct damage to animals is available as a result of proper use of currently labelled herbicides. However, take all precautions to prevent drift and damage to susceptible plants in the vicinity.

Methods of chemical application: Methods of application depend on the species, terrain, and size of the area. In most extensive range weed control projects, the herbicide is applied by aircraft, either fixed-wing or helicopter. However, ground equipment is also used successfully. On small areas and for spot treatments, ground or hand equipment is often most economical.

Some pastures contain poisonous plants. Grazing livestock normally do not eat many poisonous plants, but sometimes the composition of plants change after spraying. This can make some plants more palatable. Do not graze pastures known to have poisonous plants for at least 3 weeks after spraying.

Spot-spray to control perennial weeds in pastures. Follow recommendations to control specific weeds.

Many crops are grazed or used for pasture. When areas not generally defined as pasture are to be grazed, examine the herbicide label to determine what grazing restrictions apply before using the herbicide.

Caution: This handbook is not intended as a complete guide to herbicide use. Before using any chemical, read the label on the container. Before a chemical can be recommended for a specific use, it must be thoroughly tested. The recommendation on the manufacturer’s label, when followed, can prevent many problems arising from the wrong use of a chemical.

A note on generic products: Many active ingredients are no longer under patent protection of the original registrant and are available under multiple trade names from different manufacturers. Pricing can vary meaningfully between trade names, as can active ingredient concentration, surfactant loading, and other formulation characteristics. Trusted retailers and consultants should be able to assist in identifying and comparing competing formulations of the same active ingredient. Several free, online search tools also facilitate searching and comparing formulations by active ingredient, and trade name including those from Agrian, CDMS, Farmers Business Network, and Greenbook. In the following section, a limited number of trade names are presented per active ingredient for general reference. If generic products are available for an active ingredient, ‘several products’ or ‘several others’ is used to indicate the availability of other commercial formulations.
A note on premix products: Many herbicide formulations for use in range and pasture include various combinations of two or more active ingredients. In most cases, these active ingredients are also available as stand-alone formulations. In the following listing, only stand-alone formulations are considered, unless an active ingredient is only commercially available in a premix product. A table of pre-mix formulations is included at the end of the section, and includes many popular herbicide formulations and trade names used in range and pasture.