Frequently Asked Questions

How much herbicide do I put in my sprayer?

The mix amount is dependent on your spray volume and your application rate. Therefore, this question cannot be answered until we know the volume that is being applied with your particular sprayer in gallons per acre (GPA). The following step-by-step procedure will allow you to calibrate your spray volume. See 'How do I calibrate my spray equipment' below.

How do I calibrate my equipment?

All equipment must be calibrated in order to accurately and safely apply herbicide.

The University of Wyoming has created a great hand-out for calibrating any equipment with a handgun : Univ. of WY 1/128 Method of Calibration; Sheridan County Weed and Pest created an excel sheet to aid in the calculations: Calibration Worksheet
For equipment with a handgun please watch this how-to video: Handgun Calibration
For larger equipment with a boom sprayer please watch this how-to video: ATV Boom Calibration

How do I clean my equipment?

Rinse and flush equipment after use.
Dispose of rinse water away from water supplies.
Rinse a second time adding household ammonia- 2oz/gallon of water.
Circulate through equipment and let stand for several hours.
Flush the solution out of the handgun or boom.
Rinse the system and circulate twice more with water.

How do I clean the empty herbicide container?

All containers must be triple rinsed and recycled. The triple rinse procedure is as follows:
Empty the remaining contents into your application equipment and allow to drain for 10 seconds.
Fill container ¼ full with water and shake with lid tightly secured for 10 seconds.
Empty and drain into equipment.
Repeat two additional times.
Make sure to puncture the container so that is cannot be mistakenly used for anything else.

I don't want to use herbicides. What other options do I have?

The Wyoming Weed and Pest Council promotes Integrated Weed Management (IWM). This approach uses multiple control techniques with the specific goals of; decreasing costs, increasing control, creating synergistic effects, monitoring success, and continued effort.

IWM methods include-

  • Cultural control – modifying behaviors to prevent noxious weeds from being introduced and includes; education, prevention, early detection of new invasions, modifying grazing habits, replanting disturbed or previously infested areas with native species, and monitoring successes and failures.
  • Physical control – this is the use of physical or mechanical methods to control weed infestations. Physical control can be; mowing, chopping, pulling, cutting, burning, and tilling. Remember to identify what weeds are to be controlled, as some physical control methods can aggravate root spreading perennial weeds! Mechanical Control Video
  • Biological control – this is the use of introduced competition or predation. Often introduced noxious weeds are problems because they have been removed from their natural enemies. Biological control includes introducing insects, predators, and pathogens to control weeds as well as correctly timed grazing by species that will eat the weeds.
  • Chemical control – is the use of herbicides to control weeds. This is often the most effective control technique and if used correctly can safely and greatly reduce infestations.

In summary a good IWM plan will be a mix of all of these techniques, please consult your local Weed & Pest District for help in creating your comprehensive control plan as these may vary depending on property size, weeds present, and extent of infestation.

What are surfactants?

When considering your options for difficult to control weed species, the selection of an appropriate surfactant or adjuvant can be nearly as important as choosing the appropriate herbicide. Adjuvants and surfactants are additives to your spray solution that make your control efforts more effective. The most common surfactant is a non-ionic surfactant. These surfactants work by helping to break the water tension of your spray droplets allowing each droplet to better spread out across the leaf surface – increasing the potential for the herbicide to do its job. In a bind, you can try using a couple of drops of dish soap to create a similar effect but, soap is ionized and can potentially impact your herbicide's effectiveness.

For plants that have a thick waxy cuticle like Dalmatian toadflax or for plants with a hairy leaf like houndstounge - a more complex surfactant might improve your results. Many Districts have started using a three way blended surfactant that includes; a non-ionic surfactant, methylated seed oil, and a wetting agent. These surfactant blends allow the herbicide to stay on the plant with better coverage while helping to successfully penetrate the cuticle.

So the next time, you're not seeing the results you expected instead of adding more active ingredient – consider trying a surfactant to improve your results; it's probably cheaper and it's likely better for the environment.

How do I certify my forage as weed free?

  • How to request an inspection?
    • Please consult your local Weed & Pest District and request an inspection.
    • Please allow a minimum of 7 days for inspection.
  • What is inspected?
    • Any field with a harvestable hay, straw, or forage product.
    • Surrounding ditches, fence rows, easements, roads, and stack yards are also included.
  • Who should request inspections?
    • Producers who will be transporting, selling, or using their product for use on or traveling through lands requiring North American Weed Free Certified Forage.
    • Many federal and state lands require certified forage.
  • Where is the product inspected?
    • Product must be inspected in the field of origin.
  • When should product be inspected?
    • Forage must be certified within 7 days of harvest.
  • Why should producers have their fields inspected
    • Producers who are interested in adding a measure of quality to their product.
    • Producers who are interested in learning and developing a weed management plan for their field.

Why should I purchase weed free forage?

  • What is certified weed free forage?
  • Who should use weed free forage products?
    • Anyone who will be using on or transporting forage through federal lands.
    • Anyone who uses forage products and wishes to reduce the risk of introducing invasive weeds onto their property.
  • When should I use weed free forage?
    • Always!
  • Why should I use weed free forage products?
    • Weed free forage ensures the product you are using is free of invasive weeds.
    • Invasive weeds costs billions of dollars every year to control.
    • Invasive weeds threaten natural and agricultural resources.
    • It is a good land stewardship practice.
  • How do I know the forage I use is certified as North American Weed Free Forage (NAWFF)?
    • One of three marking systems will accompany the product.
      • Bales will be tied with official NAWFF colored twine.
      • Or, an official NAWFF tag will be attached to each bale.
      • Or, an official NAWFF transit certificate will accompany the load from its origin to its final destination.

Where can I purchase weed free forage?

Wyoming Weed Free Forage
North American Weed Free Forage

Where do I find information about becoming a licensed applicator?

The Wyoming Department of Agriculture website contains all the information you will need in order to learn about completing your applicator exam. Please visit their website at: WY Dept. of Agriculture- Pesticide Applicator Training

I have this purple weed in my yard what is it?

Please see our webpage of State Designated Noxious Weeds for information on identification.

How close can I spray to trees?

Please follow the directions on the label or consult your local Weed & Pest District.

How do I find employment opportunities?

Most Districts start the process of hiring summer employees each spring. Please consult your local Weed & Pest District directly for details. Full time positions will be listed in our News section.

Are herbicides safe for my pets and the environment?

All of the Weed and Pest Districts make a concerted effort to use the best management practices available and the safest pesticides for staff, residents and the environment. For details on specific products please consult your local Weed & Pest District.