Agronomy Blog

Liberty® Herbicide Works to Controls Weeds

by Mark Seem | Nov 1, 2017

There are weeds that have producers moving from a glyphosate weed control program to a glufosinate weed control program.  Glufosinate is the active ingredient in Liberty® herbicide. This switch has been forced by the spread of glyphosate resistant weeds due to continual and repetitive use of only glyphosate across wide geographies of the United States. Among the most common and yield damaging weed species are Palmer amaranth, waterhemp, marestail, common ragweed and giant ragweed. Cost to control these weeds can exceed $100 per acre. It should be noted that many of these glyphosate resistant weeds are also resistant to ALS herbicides, PPO herbicides among others.

LL-dense-palmer-spots-UT citedLL-Glyphosate-resistant-ragweed-corn UNL citedLL-common ragweed in soybean UofI cited

Liberty herbicide is very effective in controlling annual weed species in LibertyLink® cropping systems. Currently it is the only nonselective herbicide that is effective on these hard-to-control grasses and weeds. It is fast acting and results are visual within days of the application. There is no known resistance to Liberty herbicide.

A successful herbicide program utilizing Liberty has to include a comprehensive program of pre-plant options, pre-emergence residual herbicides and Liberty applications to be fully effective, and reduce the risk of developing additional weed resistance and protect the long-term sustainability of the Liberty technology.

Do Not Plant “green”

  • Control weeds before planting with either a conventional tillage program and/or a complete burndown treatment
  • Several of the references below make specific burndown herbicide recommendations


    Utilize Residual herbicides

  • A residual herbicide does several things
    • Reduces weed populations
    • Slows weed emergence
    • Provides flexibility to future use of post-emergence herbicides, including Liberty
    • If warranted, and the targeted weeds are 6-10” tall – up to 36 fl ox/A may be applied
      • Remember that the maximum seasonal application is 65 fl oz/A
    • Dense populations of ragweed and palmer are best controlled with 2 applications
      • First application when weeds are small, and a second application 2-3 weeks later
  • Always use labeled rates
  • Use a residual that has action on the troublesome broadleaves and that also suppresses grasses
  • Several of the references below make specific pre-emergence herbicide recommendations for individual targeted weed species


    Post-emergence applications of Liberty

  • Remember that Liberty (glufosinate) activity on weeds is MAXIMIZED in warm, sunny weather
  • Weed size
    • Target 3-6” weeds with 29 fl oz/A
      • Less than 4” for Palmer Amaranth andwaterhemp
  • Rain fastness – not following the rain fast interval can result in less than desired control
  • Stress can affect the effectiveness of the Liberty
    • Drought, cool temperatures, extended periods of cloudiness
  • Research has shown that the best weed control occurs when spraying is accomplished between 2 hours after sunrise and 2 hours before sunset
  • Avoid spraying when heavy dew, fog, mist or rain in present
  • If grasses such as barnyardgrass, crabgrass and yellow foxtail are not adequately controlled by the residual pre-emergence herbicide, consider a tank mix of Liberty and a grass herbicide. Several of the references below make specific grass herbicide recommendations.
  • Consider the addition of a tank mix partner of a residual herbicide to control late emerging grasses and/or small seeded pigweeds (Palmer or waterhemp). This may extend the window for a second application of Liberty, or provide enough control as to not warrant that second application. Several of the references below make specific herbicide recommendations for tank mix partners.
  • Sprayer considerations
    • Thorough spray coverage – minimum of 15 gallons/acre. Improved control in dense weed populations can be achieved at 20 gallons/acre
    • Medium to coarse nozzle sizes (250-350 micron droplet size). Fine nozzles may cause drift.
    • Ammonium Sulfate must be used as an adjuvant at a rate of 3 lbs/A.

Removing weeds when small prevents competition with the crop being produced, and also prevents the potential of yield losses. The economic rationale for removing all weeds in a herbicide weed control system is the protection against eventual weed resistance.

LL-Weeds in Soy - DTN citedLL-Liberty Herbcide works - AgProfessional cited

Sources and Additional Information[GOO]-[Brand_Liberty]-[e]-S-[liberty%20herbicide]&xts=519127&sc_camp=0628953356604BF8A8DC967636C5C0D3

Note: The information in this issue is based upon field observations and third party information. Since variations in local conditions may affect the information and suggestions contained in this issue, LG Seeds disclaims legal responsibility therefore. Always read and follow label instructions.
LibertyLink®, Liberty® and Innovation Plus™ are trademarks of Bayer CropSciences.
LG Seeds and design are trademarks of SCA Limagrain.

  Download a copy of this technical bulletin: Tech_325 - Using Liberty Herbicide updated 11-2017