Linex Guards Alfalfa Against Hard-to-Control Weeds

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Guard your alfalfa from Shepherd’s Purse, Mustards, Groundsel, and other hard-to-control weeds.

Linex® 4L (linuron) is a valuable Group 5 herbicide for growers faced with combatting resistant weeds. The continuous use of triazines, i.e. atrazine and metribuzin can result in the development of triazine resistant weeds in fields. As a urea-based herbicide, Linex 4L classified in the C2 group of PSII inhibitors, has a different attachment site to the D1 protein compared to that of metribuzin and atrazine. It provides broad-spectrum control of dozens of tough grasses and broadleaf weeds in dormant and in-between cutting applications.


What is the active ingredient in Linex 4L and what is the class of chemistry of the active ingredient?

The active ingredient in Linex 4L is linuron. Linex 4L contains 40.6% linuron. Linuron belongs to the substituted urea class of chemistry.

What type of activity does Linex 4L have?

Linex 4L has a triple mode of action, contact, moderate residual, and selective activity in certain crops. It has both pre-emergent and post-emergent activity.

What type of weeds are the best controlled by Linex 4L?

Linex 4L is the most active on annual broadleaf weeds. For a complete list of weeds please review the label.

What will be the Pre-harvest interval (PHI) for Linex 4L in alfalfa?

The PHI for Linex 4L in alfalfa will be 22 days.

Application Rates and Pre-harvest Intervals

Application Rate (pt/acre) Number of app. PHI (days)



1 (to moist soil following with 2 in Irrigation or rainfall)


Between cuttings


1 (before alfalfa is 2 in tall before first irrigation)


Application Recommendations


  • Make a single application as a broadcast spray near the end of winter dormancy, prior to green-up with a non-ionic surfactant spray additive which is approved for alfalfa.
  • In irrigated areas, best results are obtained when application is made to moist soil, followed within 2 weeks by 1 to 2 inches of sprinkler irrigation (or rainfall). On powder dry soils, irrigate prior to herbicide application and follow with sprinkler irrigation to activate the herbicide.

Between cuttings

  • Make a single application when alfalfa is not taller than two inches prior to first irrigation. Apply using spray volumes of 10 to 50 gallons per acre and a non-ionic surfactant spray additive which is approved in alfalfa.

Best activity of Linex 4L is recorded on the following weed species:

  • Dormant application: Shepherd’s purse, Mustards, Purslane, Lambsquarters, Pigweed, Barnyardgrass, Foxtail
  • Between cutting applications: Groundsel, Lambsquarters, Mustards, Pigweeds, and Purslane.

Features and Benefits of Linex 4L

  • Linex 4L is a water-soluble liquid that is applied by foliar application to control many important weeds
  • Linex 4L can be used as PRE or POST application and is a frequent tank mix partner, especially when used between cuttings
  • Linex 4L controls a broad spectrum of grass and broadleaf weeds
  • Because it belongs to a different sub-group of chemistry (Group 5, C2 group of PSII inhibitors), breaks the cycle of continual triazine use and can result in better control of resistant weeds.
  • Linex 4L has longer residual effects than metribuzin. Please follow label for crop rotation directions.

Why Use Linex 4L?

Why Use Linex 4L?