Invasive Grasses Management
Invasive grasses, such as downy brome (cheat grass), red brome and medusa head, are long-armed. They are designed so that
the seeds will be carried by livestock and other animals and not eaten by them.
Controlled fire is an effective treatment for many invasive grasses; however, prescribed burns often are not
possible during hot dry summer periods when grasses have produced seed, the stage at which burning would be most
effective. Some grasses, like purple fountaingrass and bufflegrass, are fire tolerant and may even respond by improved production.
Herbicides that have proven effective for controlling invasive grasses include glyphosate, imazapic, sulfometuron,
hexazinone and grass-specific herbicides (such as fluazifop-p-butyl). Effectiveness varies with grass species and some
herbicides are less damaging than others to native, desirable grass species. For example, glyphosate is effective for
cheat grass control at 2-8 leaf stage, but it is not selective and will eliminate all other vegetation as well.
Imazapic at an application of 4 oz/acre preemergence provides reasonably good control of many undesirable species,
while not decimating many native grasses.
Read the label. You must follow the label directions for all pesticides to get the best results. Failure to follow
labeled instructions may result in poor control, environmental damage, and wasted time, money and resources. If you have
questions, contact a crop consultant, Extension specialist or County Extension Agent.
Southwestern Noxious/Invasive Weed Invasive Grasses Excerpt:
Excerpted from July 2004 presentation short course, Farmington, NM, by Joseph DiTomaso,
Extension Weed Specialist, University of California-Davis firstname.lastname@example.org
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||Narrator: The timing of prescribed burns is critical for invasive grasses. They must be burned while the seeds are still on the plants.
||Joseph DiTomaso: And it's because when a seed falls to the ground, a grassland fire doesn't develop enough heat to kill a seed on the soil surface. It only gets to 200 degrees Celsius and the exposure time is just a couple of seconds. Not hot enough. If you are directly in the flame, you need only 1 to 2 seconds of exposure and you can kill that seed, which you do get. You get 3-4 seconds in a grassland fire of direct exposure to flames.
|Narrator: For more information, contact a state Extension specialist or your local County Extension Agent.
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