Weed Watch: Waterhemp

 

Waterhemp

Waterhemp is a notorious member of the pigweed family, known for its tough-to-manage resilience and ability to develop resistance. The good news is, farmers can still fight waterhemp with proper use of existing technologies and effective management strategies.1

 

Waterhemp is most common in the Midwest but is found from Texas to Maine.2,3

 

Season-long competition by waterhemp can reduce soybean yields by 44%4,5

 

Young Plants

Waterhemp can grow up to 1-1/4 inches per day. Seedlings are hairless and have longer, pear-shaped leaves that look waxy or glossy.5

 

Mature Plants

Waterhemp can range from mere inches up to 12 feet tall but generally grows to about 4 or 5 feet in most agronomic settings.3

 

Seed Pain Points

A prolific seed producer, generally producing 250,000 seeds per plant, but some can produce 1 million or more under optimal conditions.4

Waterhemp has a remarkable ability to adapt to control tactics and has developed resistance to many different classes of herbicides. It is critical to follow your management practices vigilantly to avoid this troublesome weed taking over your fields. Cultural practices that enhance the competitiveness of the crop, such as narrow row spacing or optimal soybean planting populations, help improve the consistency of your herbicide program.4

Keys to Managing Waterhemp4,5

  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.