Chemicalsamvacimpact

Impact

AMVAC · EPA Reg 5481-524 · Herbicide Document last checked 2026-05-30

According to the label From the product label

These details were extracted from this product's label PDF. The label is the law. Confirm every rate, site, restriction and safety requirement against the label before mixing or applying. Check for a state supplemental label; a product may be restricted or prohibited in a state or site even when a rate appears below. · EPA registration data for Reg. 5481-524 →

IMPACT is a systemic herbicide used for the selective control or growth suppression of emerged broadleaf and grass weeds in corn (including field corn, seed corn, popcorn, and sweet corn). The active ingredient is Topramezone (0.044 lb per fl oz). It works by inhibiting carotenoid biosynthesis (HPPD inhibitor, Group 27). It can be used in both conservation and conventional tillage crop production systems. For optimal results, apply to emerged weeds that are actively growing and before they exceed labeled maximum sizes. The product can be applied as a single or sequential application, up to 45 days prior to corn harvest. It can also be tank-mixed with other herbicides to provide a broader spectrum of control. Note that IMPACT applications should include recommended spray additives for best performance. Always follow specific directions for tank-mixing and use appropriate nozzles to ensure adequate coverage and minimize drift.

Pests covered (2)
emerged broadleaf and grass weedsBroadleaf Weeds
Areas treatable (1)
corn (field corn, seed corn, popcorn, and sweet corn)

How to treat each type of area 1

corn (field corn, seed corn, popcorn, and sweet corn)

emerged weeds actively growing
Target pest Location Rate Unit Label notes
emerged broadleaf and grass weeds Outdoor 0.75 to 2.0 fl oz per acre fl oz per acre Apply before weeds exceed labeled maximum size. Do not apply within 30 feet of sensitive plant community.

Mixing instructions 1

For pests Amount Per Label notes
broadleaf and grass weeds up to 2.0 fl oz per acre May be tank-mixed with other herbicides. Use recommended spray additives. When mixing with atrazine, use MSO or HSMOC adjuvants.

Worker safety

Re-entry interval (REI) 12
PPE required Long-sleeved shirt and long pants; chemical-resistant gloves (barrier laminate, polyethylene, Viton ≥14 mils, rubber ≥14 mils, or polyvinyl chloride ≥14 mils); shoes plus socks.

Timing & weather

Use restrictions 1

Label SDS
Publication withheld. This catalog record has no active evidence summary, so its document and any extracted directions remain unavailable while identity and document role are reviewed.

Document text and citations

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Reference only. Always read and follow the most current EPA-approved label on the product container. State and local restrictions may apply that are not reflected in this digitised copy. Verify the EPA registration number and revision date before use.