Weed Watch: Marestail



Marestail, also known as horseweed, can follow a winter or summer lifecycle and grows rapidly - and once this troublesome weed grows above 5 inches, it can be difficult to control with herbicides alone.1,2


This annual broadleaf weed is native to North America but can now be found worldwide.3


Failure to rein in its growth early can reduce yield by 40%.4


Young Plants

Up to 90% of fall emerged seedlings can survive winter and "bolt" in spring.5


Mature Plants

Leaves are entirely without petioles, and solid stems can reach 6 feet, while root systems consist of short taproots with fibrous secondary roots.6


Seed Pain Points

Seeds are numerous as each plant can produce up to 200,000 SEEDS, and 80% of these seeds can germinate immediately after falling from the mature plant.7

The evolution of herbicide-resistant and tough-to-control marestail is widespread. Keep weeds from affecting your bottom line by using well-designed best management practices, including a fall and spring burndown treatment, as well as residual herbicides to control weeds after planting. An integrated approach combining different sites and modes of action along with cultural practices can protect fields now and help prevent resistance in the future.

Keys to Managing Marestail

  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.

A Closer Look At Postemergence Application

The key to controlling marestail is all about the right timing and the right products. Apply a postemergence herbicide 20-30 days after planting, when marestail weeds are less than 4 inches tall and easier to control. Choose the right products with the right modes of action to give your crops the best defense against weeds:

XtendiMax® herbicide with VaporGrip® Technology 
  • XtendiMax® herbicide with VaporGrip® Technology, a restricted use pesticide, gives you up to 14 days of soil activity on certain small-seeded broadleaf weeds and is an effective tool to control emerged marestail*
Warrant® Herbicide 
  • Warrant® Herbicide provides excellent levels of residual control on small-seeded broadleaf and grass weeds
Roundup PowerMAX® 
  • Roundup PowerMAX® herbicide controls emerged broadleaf weeds and grasses

With the right postemergence application, as part of a complete strategy, you can keep better control of weeds and help protect your crops to canopy.

Choose the System That Means Results

Choose the system that gives you advanced weed control and yield potential.

See System Overview