Weed Watch: Palmer Amaranth

 

Palmer Amaranth

Palmer amaranth, also infamously called Palmer pigweed, is well-known for its aggressive growth and can often seem overwhelming to farmers. But with a zero-tolerance policy against weeds, you can turn the odds in your favor.1,2

 

Native to the southwestern U.S., Palmer amaranth is now found in 39 of the 48 continental U.S. states.3

 

In soybeans, Palmer amaranth can create yield losses of up to 79%.2,4

 

Young Plants

Often confused with similar weeds, plants can grow 2-3 inches per day. Leaves are diamond- to egg-shaped and often have a symmetrical leaf arrangement with a poinsettia-like appearance.2,5

 

Mature Plants

Uncontrolled plants can reach 10 feet, and no other pigweed species has terminal panicles that can reach 1-1/2 feet long.6

 

Seed Pain Points

A single plant can produce up to 1 million seeds and be responsible for generations of weeds in the same growing season.1,7

Palmer amaranth plants germinate from early spring all the way through the first killing frost, which means multiple products with multiple sites of action are needed to prevent weeds from getting big enough to produce. Palmer amaranth has rapidly gained a foothold in the U.S., and it is important to develop a weed management strategy to help prevent it from spreading.1,3

Keys to Managing Palmer Amaranth1,3,4

  1. Rotate crops

    to diversify herbicide programs and weed control strategies.

  2. Start clean

    with a burndown herbicide or tillage.

  3. Apply a pre-emergence residual application,

    using a residual product within 2 weeks before planting or prior to crop emergence.

  4. Apply a postemergence application to target small weeds early,

    before weeds grow taller than 4 inches.

  5. Prevent Seed Production.

    If weeds escape, use tillage or physically remove them before plants produce seed.