Herbicide label
Primero Herbicide Label
Primero (EPA 83100-8-83979) is a Group 2 nicosulfuron herbicide labeled for 4 crops. The label lists 55 controlled weeds, plus partial-control, suppression, and partner-control categories.
Primero label facts
- Product Primero
- EPA Reg. No. 83100-8-83979
- Distributor Rotam North America, Inc.
- Active ingredient nicosulfuron
- MOA group 2
Crops on the Primero label
Primero is labeled for these 4 crops and uses, per the EPA label.
Weeds on the Primero label
The Primero label names 60 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 control55- amaranth, palmer
- barnyardgrass, common
- burcucumber
- cocklebur, common
- dandelion
- eveningprimrose, cutleaf
- foxtail, bristly
- foxtail, giant
- foxtail, green
- foxtail, yellow
- jimsonweed
- rhizome johnsongrass
- johnsongrass, seedling
- kochia
- lambsquarters, common
- morning glory, annual
- morningglory, ivyleaf
- morningglory, pitted
- mustard, wild
- nightshade, black
- nightshade, eastern black
- oats
- wild oats
- panicum, browntop
- panicum, fall
- panicum, texas
- pigweed, redroot
- pigweed, smooth
- pusley, florida
- quackgrass
- radish, wild
- ragweed, common
- ragweed, giant
- rye, volunteer
- ryegrass, italian
- ryegrass, perennial
- sandbur, field
- sandbur, longspine
- shattercane
- sicklepod
- sida, prickly
- signalgrass, broadleaf
- smartweed, ladysthumb
- smartweed, pennsylvania
- sorghum almum
- sunflower, annual
- timothy
- triticale, volunteer
- velvetleaf
- waterhemp, common
- volunteer wheat
- millet, wild-proso
- muhly, wirestem
- witchgrass
- cupgrass, woolly
Suppression
suppression2- dogbane, hemp
- thistle, canada
Controls with a tank-mix partner
needs partner3- lambsquarters
- pigweed
- ragweeds
Primero 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.
Get the rate for your field: build a program and FieldMarshal gives you the exact per-acre rate for your crop from the label line.
Plant-back and rotation
Your interval depends on your application rate and the rotational crop.
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.
Primero FAQ
What weeds does Primero control?
The Primero label names 60 weeds, including palmer amaranth, common barnyardgrass, burcucumber, common cocklebur, dandelion, and cutleaf eveningprimrose. Control varies by crop, rate, and timing.
What crops is Primero labeled for?
Primero is labeled for 4 crops and uses, including field corn, seed corn, popcorn, and sweet corn.
What is the active ingredient in Primero? Is it a generic?
Primero's active ingredient is nicosulfuron (MOA Group 2). Other products list the same active ingredient; rates, formulations, and labeled crops differ — verify each on its own label.
Sources
Last updated 2026-09-30.