A single Palmer amaranth plant can deposit as many as 1 million seeds in the soil bank.
Driver weed resistance to glyphosate has forced growers in the Southern U.S. to shift their strategies to protect their cotton and soybean yields.
The Impact of Ignoring Resistance
Palmer amaranth and other glyphosate-resistant weeds can completely devastate cotton yields. According to the Weed Science Society of America, left uncontrolled, a single glyphosate-resistant Palmer amaranth plant can deposit as many as 1 million seeds into the soil seedbank. Other weed species – including waterhemp and marestail – have also shown aggressive resistance.
According to a USDA Economic Research Service study, glyphosate-resistant weeds are even more prevalent on soybeans acres. The study estimated that growers of continuous soybeans can realize an extra $22.60 per acre return by proactively managing resistance. This serious threat of economic losses from glyphosate-resistant weeds demands soybean growers’ attention to use alternatives.
Experts agree that zero tolerance is an important way to stop the spread of resistant weeds. Read more on zero tolerance, alternatives to glyphosate and best management practices.
Choosing an Herbicide Program
To sustainably manage weeds in the South, implement a well-planned herbicide program that employs multiple sites of action, including the use of an SOA with residual activity. Before applying any herbicide, make sure to read the entire label to get the best possible results and confirm that the product's chemistry is effective on the weeds you wish to control. No product fits the needs of every situation, and using the correct application technique will ensure the best results.
Liberty® herbicide (10) contains the only working non-selective post-emergence herbicide that effectively handles grasses and broadleaf weeds, including glyphosate-resistant Palmer amaranth, giant ragweed, false ragweed, marestail, waterhemp and kochia.* Proper application of any herbicide is essential to maximize control.
Solutions for Cotton
The LibertyLink® trait couples high-performing genetics with excellent weed control from Liberty herbicide. With a unique site of action, Liberty can stop tough-to-control and glyphosate-resistant weeds.
Cotton growers may also choose cotton varieties with a GlyTol® trait, which enables tolerance to glyphosate. Growers who plant FiberMax® or Stoneville® cotton varieties stacked with the GlyTol and LibertyLink traits gain increased flexibility to tackle tough weeds while keeping crops safe and yields high.
Growers should check bag tags. Some commercially available FiberMax cotton varieties do not contain both the GlyTol and LibertyLink traits.
Solutions for Soybeans
Bayer offers soybean growers strong programs for season-long weed control. One recommended program starts with LibertyLink soybeans. The LibertyLink trait is available in a wide variety of brands, including Credenz® soybeans, which offer tailored varieties to fit any field conditions. The use of Liberty (10) herbicide in combination with a residual pre or post tankmix partner offers powerful weed control. Finish with Autumn™ Super (2) in the fall after harvest.
Learn more about using herbicides with effective sites of action with our Trait and Technology Use Manual.
*The active ingredient in Liberty is a Group 10 herbicide, which is the only broad-spectrum herbicide that effectively controls grasses and broadleaf weeds, and it has no known resistance in U.S. broadacre crops.