Reviewed September 2026 against EPA Office of Pesticide Programs registration records, USDA Forest Service Research & Development, USDA NASS, and FBN Canada’s product catalog.

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There is no herbicide registered with the EPA, in USDA NASS chemical-use surveys, or in Canadian pesticide approval records under the name “Par 111.” What turns up instead is Par III, a turf herbicide sold in Canada containing 2,4-D, dicamba, and MCPP-p, and Velpar, a hexazinone-based herbicide registered with the EPA since 1975 for forestry and pre-plant use in corn and sugarcane. If you were handed a jug or a label reading “Par 111,” the fastest way to resolve it is to read the EPA registration number printed on the label and look it up directly — we show you how below, alongside what Par III and Velpar actually contain and where each is used.

“Par 111” vs. Par III: Clearing Up the Name

Searches for “par 111,” “par iii,” “par 3 herbicide,” and “par 3 weed killer” are, almost certainly, all landing on the same product family, split by an OCR or transcription quirk: the Roman numeral III in “Par III” gets read as the digits “111” or the number “3” depending on the font, the label scan, or the person typing it into a search box. We checked the EPA’s pesticide product label search and USDA NASS’s Agricultural Chemical Use Program for any registration under “Par 111” or “Par 3” as distinct products — neither returns a match. What does exist is Par III turf herbicide, currently listed by FBN Canada with a specific active-ingredient makeup (below), sold for turf and non-crop vegetation control rather than row-crop pasture or rangeland use.

This matters because a farm manager searching “par 111 herbicide” while holding a jug is trying to answer one question: what is this and how do I apply it correctly? Getting that wrong — spraying a turf-labeled product on forage or rotational cropland — is a label violation, not just an efficacy problem. So the first move with any unfamiliar container is not a search engine; it’s the EPA registration number stamped on the label itself.

Par III vs. Velpar: Side-by-Side Comparison

Par III Herbicide: Active Ingredients & Use

Par III turf herbicide, as currently listed by FBN Canada, combines three active ingredients at fixed concentrations: 2,4-D at 190 grams per liter, MCPP-p (mecoprop-p) at 100 grams per liter, and dicamba at 18 grams per liter. This is a three-way broadleaf mix, a formulation pattern common in turf and lawn-care herbicides rather than row-crop or pasture products — 2,4-D and MCPP-p both disrupt broadleaf plant growth hormones, while dicamba adds control of harder broadleaf species that resist the first two alone.

Because FBN Canada lists this specifically as a turf herbicide, it is not the same use category as a pasture or rangeland product. If you are managing forage, rotational cropland, or rangeland and were told to look for “Par 3” or “Par 111,” confirm with your input supplier whether they actually mean this turf-labeled product or a different one — using a turf herbicide off-label on grazed pasture or a rotational crop field risks both crop injury and a label violation, independent of whether it would technically control the target weed.

Application rates, re-entry intervals, and buffer-zone requirements for Par III are set on the product label itself, not published in the general catalog listing we reviewed — the FBN Canada page confirms the active-ingredient makeup but does not itemize a per-hectare rate table. If your supplier can provide the specific label PDF (Canadian products carry a Pest Control Product, or PCP, number issued by Health Canada’s Pest Management Regulatory Agency), that document is the authoritative rate source, not a search result.

Helpful Resources

For agronomists tracking exactly what was applied where, and needing that record later for compliance or export documentation, Farmonaut’s traceability platform logs herbicide application alongside crop performance data — useful regardless of which specific product a field record refers to.

Velpar Herbicide: Hexazinone, Rates & Timing

Velpar’s active ingredient is hexazinone, first granted EPA registration in 1975, according to the US EPA Office of Pesticide Programs reregistration fact sheet for PC-107201. The current EPA-registered label for VELPAR L CU (label dated September 29, 2020) lists the liquid formulation at 25% hexazinone concentration. For site preparation use, the label specifies an application rate of 2 to 6 quarts per acre, delivering 1 to 3 pounds of active ingredient hexazinone per acre.

Timing matters more with hexazinone than with faster-acting broadleaf herbicides. USDA Forest Service research (Research & Development, treesearch record 5223) found that hexazinone reaches effective weed control within about 1 month of application, but tree control — the woody, perennial target most relevant to forestry site prep — takes 3 to 10 months to show full effect. That gap is the reason Velpar site-prep programs are planned a season ahead of planting, not sprayed and planted in the same window.

Velpar’s labeled uses extend beyond forestry: the EPA label also covers pre-plant applications in corn and sugarcane. Scale context for US corn acreage: USDA NASS reported 91.5 million acres of corn expected for harvest in 2024 nationally — a figure NASS republishes each year in its June acreage report, so check the USDA NASS acreage release for the current year’s number rather than reusing the 2024 figure going forward. Cotton, a crop sometimes discussed alongside pre-plant herbicide programs, covered 11.7 million acres planted in the US in 2024 per USDA NASS county-level crop acreage data — again, a figure NASS updates annually and searchable directly through NASS Quick Stats for the current planting year.

Because hexazinone is soil-mobile and absorbed through both roots and foliage, the EPA label carries leaching precautions near waterways and in porous soils. Land managers verifying vegetation cover before and after a Velpar application can use Farmonaut’s satellite-based farm management tools to document canopy and woody-plant cover changes over the 3-to-10-month window the USDA Forest Service data describes, supporting both timing decisions and after-the-fact compliance records.

Key Limitations of Velpar

• ⚠ Soil mobility creates leaching risk into groundwater and adjacent surface water — site selection and buffer zones matter more than with less mobile actives.
• ⚠ The 3–10 month lag before woody/tree control is visible (USDA Forest Service data above) means a single-season efficacy judgment can be premature.
• ⚠ Corn and sugarcane uses are pre-plant only per the EPA label — it is not labeled for over-the-top use in an established stand.

Finding a “Par 3 Herbicide Equivalent”

If you searched “par 3 herbicide equivalent” because a specific product is out of stock, discontinued in your region, or you’re comparing options before a purchase, the right comparison point is the active ingredient, not the brand name. Par III’s actives are 2,4-D, dicamba, and MCPP-p — a common three-way broadleaf turf combination. A true equivalent would match those three actives at comparable concentrations (190 g/L 2,4-D, 18 g/L dicamba, 100 g/L MCPP-p, per the FBN Canada listing), not just share a similar-sounding name.

For Velpar, the equivalent question is really “which hexazinone products are registered in my state/province and at what concentration.” The EPA’s product label search lets you pull every registered hexazinone label by active ingredient rather than guessing from brand names — search “hexazinone” directly rather than a specific trade name, since formulations and registrants can change.

How to Verify Any Herbicide Label Yourself

This is the durable part of this article — the lookup method below works regardless of what a product happens to be branded next season:

1. Find the EPA registration number on the label — format is typically two sets of numbers separated by a dash (e.g., 061842-00047 for VELPAR L CU).
2. Search the EPA Product Label System (www3.epa.gov/pesticides/chem_search/ppls) using that registration number to pull the current, legally binding label — not a retailer’s summary page.
3. Cross-check active ingredients against the label’s ingredient statement, which lists percentage by weight for each active.
4. For Canadian products, use the Pest Control Product (PCP) number and Health Canada’s Pest Management Regulatory Agency label search instead of the EPA system.
5. For US acreage/adoption context, query USDA NASS Quick Stats (quickstats.nass.usda.gov) directly, filtering by crop, chemical, and year — the Agricultural Chemical Use Program is the source NASS itself points to for this data.
6. For Canadian crop acreage context, use Statistics Canada Table 32-10-0015-01, updated quarterly by province and crop year.

None of this requires trusting a brand name at all — the registration number and the label PDF are the only documents with legal weight, and both are free to search.

Hexazinone Rate Calculator

Enter your acreage and target active-ingredient rate to estimate Velpar L CU product volume needed for site preparation, based on the EPA label’s 2–6 quarts/acre (1–3 lbs ai/acre) range.

Assumes VELPAR L CU at 25% hexazinone (2.08 lbs ai per gallon, per the EPA label), a linear rate-to-volume relationship within the label’s 2–6 quart/acre site-preparation range, and a single uniform application. It excludes tank-mix partners, spray-water volume, terrain-based rate adjustments, and any state or provincial rate restrictions — confirm final rates against your specific product label before mixing.

Where Satellite Monitoring Fits In

Whichever herbicide a field record eventually lands on, the underlying question — did the application work, and can I prove it — doesn’t depend on the brand name. Satellite vegetation monitoring establishes a pre-application baseline and tracks canopy or weed-cover change afterward, which is the actual evidence a hexazinone program’s 3-to-10-month tree-control window (per the USDA Forest Service data above) requires to judge properly.

• 🛰️ Vegetation monitoring: Identifies weed cover before treatment and tracks decline afterward, rather than relying on a single field visit.
• 💻 Digital application records: Timestamped, geolocated logs of what was sprayed where — useful when a label’s active-ingredient identity, not just its brand name, needs to be on file.
• ⛓️ Traceability records: Supports compliance documentation independent of which specific product was used, via Farmonaut’s traceability platform.
• 🌎 Carbon and environmental tracking: Quantifies input-use efficiency over time via Farmonaut Carbon Footprinting.

With Farmonaut’s API and developer docs, agribusinesses can automate weed-detection alerts and tie them to application-timing decisions — including the kind of extended monitoring window a hexazinone treatment schedule needs. Farmonaut’s crop loan and insurance verification services also use this same satellite evidence to document stewardship practices for financing purposes.

Farmonaut Subscription Plans for Precision Monitoring

Ready to track weed pressure and application results by satellite? Explore Farmonaut’s subscription options:

Frequently Asked Questions

Conclusion

“Par 111” is very likely a misread or mistyped version of Par III, a turf herbicide with a specific, verifiable active-ingredient makeup — 2,4-D, dicamba, and MCPP-p — not a separate registered product. Velpar, built on hexazinone since its 1975 EPA registration, is a distinct chemistry used for forestry and pre-plant corn/sugarcane work, with a well-documented 3-to-10-month window before woody-plant control is fully visible. Neither name substitutes for reading the actual label in front of you.

• The EPA registration number on a label — not the brand name — is the authoritative identifier; look it up at the EPA Product Label System.
• Canadian products carry a PCP number instead, checked against Health Canada’s Pest Management Regulatory Agency database.
• USDA NASS Quick Stats and Statistics Canada Table 32-10-0015-01 are the update paths for acreage and crop-context figures cited here, both refreshed on regular public schedules.
• Satellite-based vegetation tracking gives you the before/after evidence a multi-month hexazinone control window actually requires to evaluate.

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