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Vegetation Management Herbicide Stewardship

May 3, 2016
Reducing off-target issues


When applied correctly, non-crop herbicides are useful and necessary tools to manage unwanted
vegetation that can lead to safety, financial, and economic losses. However when applied incorrectly, non-crop herbicides have the potential to cause off-target injury to desirable vegetation. Training and education about proper herbicide performance can help eliminate these risks. This results in economic, aesthetic and environmental benefits to the treatment site.


Use the following checklist as a guide before making applications. It will help you develop a low-risk and high-benefit herbicide program.

Chemical selection • Understand the herbicide solubility, mobility, persistence, and volatility properties. • Know the chemical sensitivity of adjacent vegetation, crops and ornamentals. • Match the correct herbicide, rate and timing to the target vegetation. • Research the site history and presence of resistant weeds in the area.
• Tank-mix herbicides with multiple modes of action on the target when possible. Repeated use of the same herbicide can result in resistance. • Treat weeds during optimum growth stage of life cycle for best activity. • Evaluate performance at the end of the season to consider any program upgrades needed.

Application accuracy
• Select the proper equipment and licensed personnel for the spray job.
• Use the proper nozzle type for accurate herbicide placement. Calibrate nozzles periodically for spray output accuracy.
• To reduce spray drift
- Match spray pressure, nozzles and driving speed to obtain good weed coverage while minimizing the production of fines (small droplets most prone to drift) that can lead to drift
- Apply with spray boom or nozzle height as low as possible
- Use a drift control agent as recommended by product labeling
• Use caution when making treatments next to desirable vegetation.
• Maintain detailed spray records.
• Please be aware:
- Tree or plant roots may extend or grow into the treatment area.
- Slopes will impact fixed nozzle application rates.
- Draining or flushing spray equipment near or on desirable vegetation may result in injury or loss of desirable vegetation.

Target area stability
• Sites disturbed by mechanical means or vehicle traffic may lead to herbicide inactivity or movement to off-target areas.
• Know the soil texture or road ballast composition as it relates to wind or water erosion potential, as well as herbicide leaching potential.
• Treat asphalt or concrete surfaces only if specifically directed by the product labeling.

Environmental conditions
• High wind, high temperatures and low humidity may increase potential off-target drift.
• Saturated soils, frozen soils, soil-impedance layers, sloped areas or heavy rainfall may increase potential off-target movement.
• Be cautious of passing vehicle wind shear when spraying (i.e. large trucks).
• Avoid applications to:
- Powdery, dry soils and light, sandy soils when there is little likelihood of rainfall soon after treatment
- Weeds hardened off by cold or hot weather or drought conditions
• Understand local weather patterns to make a proper timing of the herbicide treatment.
• Do not apply during a temperature inversion.
• Know the location of water bodies prior to making application. Avoid applications directly to the water’s surface.
• Observe label buffers from water and other sensitive areas.
• A heavy rain shower may cause product to dissolve and be carried to the lowest point in or near the treatment area.
• Movement of any product during a heavy rainfall is possible.
• Be aware of areas with shallow ground water tables and select herbicides accordingly.

For more information about effective vegetation management, contact your Bayer representative or visit

Bayer CropScience LP, Environmental Science Division. 2 TW Alexander Drive, Research Triangle Park, NC 27709. 1-800-331 2867. Bayer and the Bayer Cross are registered trademarks of Bayer. Please verify state registration of these products in your state before selling, using or distributing. ©2015 Bayer CropScience LP. 15BPI-042-3

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