Herbicide label

Synex 4 L

Synex 4 L (EPA 91234-323) is a Group 5 linuron herbicide labeled for 6 crops. The label lists 56 controlled weeds, plus partial-control, suppression, and partner-control categories.

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Official EPA label (PDF)

Synex 4 L label facts

Crops on the Synex 4 L label

Synex 4 L is labeled for these 6 crops and uses, per the EPA label.

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Weeds on the Synex 4 L label

The Synex 4 L label names 63 weeds and rates each by how the product handles it: full control, partial control, suppression, or control with a tank-mix partner. A weed can fall at more than one level, because control varies by crop, rate, and timing.

Controls

full control56
  • amaranth, palmer
  • aster, white heath
  • barnyardgrass, common
  • beggarweed, florida
  • buckwheat, wild
  • canarygrass
  • carpetweed
  • chickweed, common
  • chickweed, mouseear
  • cocklebur, common
  • crabgrass, large
  • deadnettle, purple
  • dayflower, common
  • dog fennel
  • evening-primrose, cutleaf
  • rattail fescue
  • fiddleneck
  • foxtail, green
  • foxtail, yellow
  • galinsoga
  • goosefoot, nettleleaf
  • goosegrass
  • groundsel, common
  • henbit
  • knawel
  • kochia
  • lambsquarters
  • morningglory, entire leaf
  • morningglory, ivy leaf
  • morningglory, pitted
  • mustard, blue
  • mustard, tumble
  • mustard, wallflower
  • panicum, fall
  • panicum, texas
  • pennycress, field
  • pigweed, prostrate
  • pigweed, redroot
  • pigweed, smooth
  • prickly lettuce
  • purslane, common
  • radish, wild
  • ragweed, common
  • ryegrass, annual
  • sesbania, hemp
  • shepherd's-purse
  • sicklepod
  • sida, prickly
  • signalgrass, broadleaf
  • smartweed, pennsylvania
  • speedwell, corn
  • speedwell, field
  • tansymustard, pinnate
  • velvetleaf
  • wallflower, bushy
  • waterhemp, common

Partial control

partial17
  • beggarweed, florida
  • cocklebur, common
  • crabgrass, smooth
  • dayflower, common
  • foxtail, giant
  • kochia
  • morning glory, annual
  • morningglory, entire leaf
  • morningglory, ivy leaf
  • morningglory, pitted
  • nightshade, eastern black
  • pusley, florida
  • ragweed, giant
  • sicklepod
  • sida, prickly
  • velvetleaf
  • waterhemp, common

Suppression

suppression1
  • deadnettle, purple

Controls with a tank-mix partner

needs partner1
  • nutsedge

Want the control level for your crop, or to filter 1,700+ labels by any of these weeds? Use the free label filter.

Synex 4 L rates and plant-back

The label answers both with a table, not a single number. Here is what drives each answer.

Application rate

Your rate depends on your crop and your soil texture.

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Plant-back and rotation

Your interval depends on your application rate, the rotational crop, and your state, region, and rainfall — some intervals differ in AL, AR, CO, CT, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, and WY.

Get the interval for your rotation: build a program and FieldMarshal gives you the exact plant-back for your rotational crop from the label line.

Synex 4 L FAQ

What weeds does Synex 4 L control?

The Synex 4 L label names 63 weeds, including palmer amaranth, white heath aster, common barnyardgrass, florida beggarweed, wild buckwheat, and canarygrass. Control varies by crop, rate, and timing.

What crops is Synex 4 L labeled for?

Synex 4 L is labeled for 6 crops and uses, including field corn, soybeans, wheat, cotton, and potato.

What is the active ingredient in Synex 4 L? Is it a generic?

Synex 4 L's active ingredient is linuron (MOA Group 5). Other products list the same active ingredient; rates, formulations, and labeled crops differ — verify each on its own label.

What's the plant-back interval after Synex 4 L?

It depends on your rotational crop, application rate, and region, so the label gives a table, not one number. Build a program and FieldMarshal gives you the exact interval for your rotation from the label line, so you can verify it.

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Can I tank-mix Synex 4 L?

It depends on your target weeds, crop stage, and which partners the label approves. Build a program and FieldMarshal checks the label for approved partners and gives the condition on each, so you can verify it.

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Sources

Last updated 2026-07-14.