crop-chem-docs/corpus/epa_ppls/100-1268.md

# PREFIX HERBICIDE

- EPA Reg No: **100-1268**
- Registrant: SYNGENTA CROP PROTECTION, LLC
- Signal word: Warning
- Active ingredients: S-Metolachlor (46.4%); Sodium salt of fomesafen (10.2%)
- Label accepted: 2025-02-02
- Source PDF: https://www3.epa.gov/pesticides/chem_search/ppls/000100-01268-20250202.pdf

---
February 2, 2025
Jordan Moseley
jordan.moseley@syngenta.com
SYNGENTA CROP PROTECTION, LLC
Subject: Non-PRIA (Pesticide Registration Improvement Act) Labeling Amendment - Revise label with
updated soybean cut-off date
Product Name: PREFIX HERBICIDE
Admin Number: 100-1268
EPA Receipt Date: 10/29/2024
Action Case Number: 00638249
Dear Jordan Moseley:
The amended labeling referred to above, submitted in connection with registration under the Federal
Insecticide, Fungicide, and Rodenticide Act, as amended, is acceptable.
This approval does not affect any terms or conditions that were previously imposed on this registration. You
continue to be subject to existing terms or conditions on your registration and any deadlines connected with
them.
A stamped copy of your labeling is enclosed for your records. This labeling supersedes all previously
accepted labeling. You must submit one (1) copy of the final printed labeling before you release this product
for shipment with the new labeling. In accordance with 40 CFR § 152.130(c), you may distribute or sell this
product under the previously approved labeling for 18 months from the date of this letter. After 18 months, you
may only distribute or sell this product if it bears this new revised labeling or subsequently approved labeling.
“To distribute or sell” is defined under FIFRA section 2(gg) and its implementing regulation at 40 CFR § 152.3.
The label submitted with the application has been stamped "Accepted Only Indicated Revisions Reviewed"
and is enclosed for your records.
Should you wish to add/retain a reference to your company’s website on your label, then please be aware that
the website becomes labeling under FIFRA and is subject to review by EPA. If the website is false or
misleading, the product will be considered to be misbranded and sale or distribution of the product is unlawful
under FIFRA section 12(a)(1)(E). 40 CFR § 156.10(a)(5) lists examples of statements the EPA may consider
false or misleading. In addition, regardless of whether a website is referenced on your product’s label, claims
made on the website may not substantially differ from those claims approved through the registration process.
Therefore, should the EPA find or if it is brought to our attention that a website contains statements or claims
substantially differing from statements or claims made in connection with obtaining a FIFRA section 3
registration, the website will be referred to the EPA’s Office of Enforcement and Compliance Assurance.
Your release for shipment of this product constitutes acceptance of these terms. If these terms are not
complied with, this registration will be subject to cancellation in accordance with FIFRA section 6.

If you have questions, please contact Elizabeth Andrews via email at andrews.elizabeth@epa.gov.
Sincerely,
Kable Bo Davis, Senior Advisor 
HB, RD
Office of Pesticide Programs
Kable Bo Davis

Prefix Herbicide 
Page 1 
 
[MASTER LABEL] 
 
Sale, use and distribution of this product in Nassau and Suffolk Counties in the 
State of New York is prohibited. 
FOMESAFEN GROUP 
14 HERBICIDE 
S-METOLACHLOR GROUP 15 HERBICIDE 
 
Prefix® Herbicide 
 
For control of certain grasses and broadleaf weeds in soybeans and cotton 
 
Active Ingredients: 
S-metolachlor* ......................................................................................................... 46.4% 
Sodium Salt of Fomesafen** ................................................................................... 10.2% 
Other Ingredients: 43.4% 
Total: 100.0% 
 
Prefix Herbicide is formulated as an emulsifiable concentrate (EC). 
 
Prefix Herbicide contains 4.34 lb of S-metolachlor and 0.95 lb of the sodium salt of 
fomesafen per gallon. 
 
 *CAS No. 87392-12-9 
**CAS No. 108731-70-0 
 
KEEP OUT OF REACH OF CHILDREN 
WARNING/AVISO 
 
Si usted no entiende la etiqueta, busque a alguien para que se la explique a usted 
in detalle. If you do not understand the label, find someone to explain it to you in 
detail. 
 
See additional precautionary statements and directions for use inside booklet. 
 
EPA Reg. No. 100-1268 
EPA Est. 
 
SCP 1268A 
 
gallons 
__________ 
Net Contents 
100-1268
02/02/2025

Prefix Herbicide 
Page 2 
 
FIRST AID 
If in eyes x Hold eye open and rinse slowly and gently with water for 15-20 
minutes. 
x Remove contact lenses, if present, after the first 5 minutes then 
continue rinsing eye. 
x Call a poison control center or doctor for treatment advice. 
If swallowed x Call a poison control center or doctor immediately for treatment 
advice. 
x Have person sip a glass of water if able to swallow. 
x Do not induce vomiting unless told to do so by the poison control 
center or doctor. 
x Do not give anything by mouth to an unconscious person. 
If inhaled x Move person to fresh air. 
x If person is not breathing, call 911 or an ambulance, then give 
artificial respiration, preferably by mouth-to-mouth, if possible. 
x Call a poison control center or doctor for further treatment advice. 
If on skin or 
clothing 
x Take off contaminated clothing. 
x Rinse skin immediately with plenty of water for 15-20 minutes. 
x Call a poison control center or doctor for treatment advice. 
Have the product container or label with you when calling a Poison Control Center or 
doctor or going for treatment. 
HOTLINE NUMBER 
For 24-Hour Medical Emergency Assistance (Human or Animal) or 
Chemical Emergency Assistance (Spill, Leak, Fire, or Accident), 
Call 1-800-888-8372 
 
 
PRECAUTIONARY STATEMENTS 
 
Hazards to Humans and Domestic Animals 
 
WARNING/AVISO 
 
Causes substantial but temporary eye injury. Do not get in eyes or on clothing. 
Harmful if swallowed. Wash thoroughly with soap and water after handling and before 
eating, drinking, chewing gum, using tobacco or using the toilet. Remove and wash 
contaminated clothing before reuse.

Prefix Herbicide 
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Personal Protective Equipment (PPE) 
 
Mixers, loaders, applicators and other handlers must wear: 
 
x Long-sleeved shirt and long pants 
x Chemical-resistant gloves made of barrier laminate • 14 mils or Viton® • 14 mils 
x Shoes plus socks 
x Protective eyewear (goggles, face shield, or safety glasses) 
 
User Safety Requirements 
 
Discard clothing and other absorbent materials that have been drenched or heavily 
contaminated with this product’s concentrate. Do not reuse them. Follow 
manufacturer’s instructions for cleaning/maintaining PPE. If no such instructions for 
washables exist, use detergent and hot water. Keep and wash PPE separately from 
other laundry. 
 
Engineering Controls 
 
Mixers and loaders supporting aerial applications are required to use closed systems. 
The closed system must be used in a manner that meets the requirements listed in the 
Worker Protection Standard (WPS) for agricultural pesticides. When using the closed 
system, the mixers’ and loaders’ PPE requirements may be reduced or modified as 
specified in the WPS. 
 
When handlers use closed systems, enclosed cabs, or aircraft in a manner that meets 
the requirements listed in the Worker Protection Standard (WPS) for agricultural 
pesticides, the handler PPE requirements may be reduced or modified as specified in 
the WPS. 
 
User Safety Recommendations: 
Users should: 
x Remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly 
and put on clean clothing. 
x Remove PPE immediately after handling this product. Wash the outside of gloves 
before removing. As soon as possible, wash thoroughly and change into clean 
clothin
g. 
 
Environmental Hazards 
 
Do not apply directly to water, or to areas where surface water is present, or to intertidal 
areas below the mean high water mark. Do not contaminate water when disposing of 
equipment wash water or rinsate. Do not apply when weather conditions favor drift from 
target area. Drift and runoff may be hazardous to aquatic organisms in water adjacent to 
treated area.

Prefix Herbicide 
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Groundwater Advisory 
 
Fomesafen and S-metolachlor are known to leach through soil into groundwater under 
certain conditions as a result of label use. These chemicals may leach into groundwater 
if used in areas where soils are permeable, particularly where the water table is shallow. 
 
Surface Water Advisory 
 
This product may impact surface water quality due to spray drift and runoff of rain water. 
This is especially true for poorly draining soils and soils with shallow ground water. This 
product is classified as having high potential for reaching surface water via runoff for 
several weeks or months after application. A level, well-maintained vegetative buffer 
strip between areas to which this product is applied and surface water features such as 
ponds, streams, and springs will reduce the potential loading of metolachlor/S-
metolachlor from runoff water and sediment. Runoff of this product will be reduced by 
avoiding applications when rainfall or irrigation is expected to occur within 48 hours. For 
more information, see the United States Department of Agriculture National Resource 
Conservation Service’s manual, “Conservation Buffers to Reduce Pesticide Losses."
 
 
Non-target Organism Advisory 
 
This product is toxic to plants and may adversely impact the forage and habitat of non-
target organisms, including pollinators, in areas adjacent to the treated site. Protect the 
forage and habitat of non-target organisms by following label directions intended to 
minimize spray drift. 
 
Reporting Ecological Incidents 
 
To report ecological incidents, including mortality, injury, or harm to plants and animals, 
call 1-800-888-8372 
 
 
Mixing/Loading Instructions 
 
Product must be used in a manner which will prevent back siphoning in wells, spills or 
improper disposal of excess pesticide, spray mixtures or rinsates. 
 
All mixing and/or irrigation equipment used for Prefix Herbicide must be equipped with 
check valves or other devices to prevent siphoning. 
 
This product may not be mixed or loaded within 50 ft of perennial or intermittent streams 
and rivers, natural or impounded lakes and reservoirs. This product may not be 
mixed/loaded or used within 50 ft of all wells, including abandoned wells, drainage

Prefix Herbicide 
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wells, and sink holes. Operations that involve mixing, loading, rinsing, or washing of 
this product into or from pesticide handling or application equipment or containers within 
50 ft of any well are prohibited, unless conducted on an impervious pad constructed to 
withstand the weight of the heaviest load that may be positioned on or moved across 
the pad. Such a pad shall be designed and maintained to contain any product spills or 
equipment leaks, container or equipment rinse or wash water, and rain water that may 
fall on the pad. Surface water shall not be allowed to either flow over or from the pad, 
which means the pad must be self-contained. The pad shall be sloped to facilitate 
material removal. An unroofed pad shall be of sufficient capacity to contain at a 
minimum 110% of the capacity of the largest pesticide container or application 
equipment on the pad. A pad that is covered by a roof of sufficient size to completely 
exclude precipitation from contact with the pad shall have a minimum containment 
capacity of 100% of the capacity of the largest pesticide container or application 
equipment on the pad. Containment capacities as described above shall be maintained 
at all times. The above-specified minimum containment capacities do not apply to 
vehicles when delivering pesticide shipments to the mixing/loading site. 
 
DIRECTIONS FOR USE 
 
It is a violation of Federal Law to use this product in a manner inconsistent with its 
labeling. 
 
Endangered Species Protection Requirements 
 
It is a Federal offense to use any pesticide in a manner that results in an unauthorized 
“take” (e.g., kill or otherwise harm) of an endangered species and certain threatened 
species, under the Endangered Species Act section 9. When using this product, you 
must follow the measures contained in the Endangered Species Protection Bulletin for 
the area in which you are applying the product. You must obtain a Bulletin no earlier 
than six months before using this product. To obtain Bulletins, consult 
http://www.epa.gov/espp/, call 1-844-447-3813, or email ESPP@epa.gov. You must use 
the Bulletin valid for the month in which you will apply the product. 
 
 
Do not apply this product in a way that will contact workers or other persons, either 
directly or through drift. Only protected handlers may be in the area during application. 
For any requirements specific to your State or Tribe, consult the agency responsible for 
pesticide regulation. 
 
AGRICULTURAL USE REQUIREMENTS 
 
Use this product only in accordance with its labeling and with the Worker Protection 
Standard, 40 CFR part 170. This Standard contains requirements for the protection of 
agricultural workers on farms, forests, nurseries, and greenhouses, and handlers of 
agricultural pesticides. It contains requirements for training, decontamination, 
notification, and emer
gency assistance. It also contains specific instructions and

Prefix Herbicide 
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exceptions pertaining to the statements on this label about personal protective 
equipment (PPE) and restricted-entry interval. The requirements in this box only apply 
to uses of this product that are covered by the Worker Protection Standard. 
 
Do not enter or allow worker entry into treated areas during the restricted-entry 
interval (REI) of 24 hours. Exception: If the product is soil-injected or soil-
incorporated, the Worker Protection Standard, under certain circumstances, allows 
workers to enter the treated area if there will be no contact with anything that has been 
treated. 
 
For early entry to treated areas that is permitted under the Worker Protection Standard 
and that involves contact with anything that has been treated, such as plants, soil, or 
water, wear: 
 
x Long-sleeved shirt and long pants 
x Chemical-resistant gloves made of barrier laminate • 14 mils or Viton • 14 mils 
x Shoes plus socks 
x Protective eyewea
r 
 
FAILURE TO FOLLOW THE DIRECTIONS FOR USE AND PRECAUTIONS ON THIS 
LABEL MAY RESULT IN POOR WEED CONTROL, CROP INJURY, OR ILLEGAL 
RESIDUES. 
 
 
PRODUCT INFORMATION 
 
Prefix Herbicide is a selective herbicide for the control or partial control of certain grass, 
broadleaf and sedge weeds in soybeans and cotton. Prefix Herbicide may be applied 
as a preplant surface, preplant incorporated, preemergence, or postemergence 
treatment in soybeans and as a post-directed treatment in cotton. 
 
WEED RESISTANCEC MANAGEMENT 
 
FOMESAFEN GROUP 14 HERBICIDE 
S-METOLACHLOR GROUP 15 HERBICIDE 
 
Prefix Herbicide contains the active ingredients fomesafen which inhibits the enzyme 
protoporphyrinogen oxidase (PPO or PROTOX, Site of Action Group 14) and 
S-metolachlor which inhibits the formation of very long chain fatty acids (VLCFA, Site of 
Action Group 15). Some naturally occurring weed populations have been identified as 
resistant to Group 14 and Group 15 herbicides. Selection of resistant biotypes, through 
repeated use of these herbicides or lower than recommended use rates in the same 
field, may result in weed control failures. A resistant biotype may be present where 
poor performance cannot be attributed to adverse environmental conditions or improper 
application methods. Contact your local Syngenta representative, retailer, crop advisor 
or extension agent to determine if weeds resistant to modes of action contained in this

Prefix Herbicide 
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product are present in your area. If resistant biotypes have been reported, use the full 
labeled rate of this product, apply at the labeled timing, and tank-mix with a different 
mode of action product so there are multiple effective modes of application for each 
suspected resistant weed. 
 
 
Principles of Herbicide Resistant Weed Management 
Scout and know your field 
• Know weed species present in the field to be treated through scouting and field 
history. An understanding of weed biology is useful in designing a resistance 
management strategy. Ensure the weed management program will control all 
weeds present. 
• Fields should be scouted prior to application to determine species present and 
growth stage. Always apply this herbicide at the full labeled rate and correct 
timing for the weeds present in the field. 
Utilize non-herbicidal practices to add diversity 
• Use diversified management tactics such as cover crops, mechanical weed 
control, harvest weed seed control, and crop rotation as appropriate. 
Use good agronomic practices, start clean and stay clean 
• Use good agronomic practices that enhance crop competitiveness. 
• Plant into weed-free fields utilizing tillage or an effective burndown herbicide for 
control of emerged weeds. 
• Sanitize farm equipment to avoid spreading seed or vegetative propagules prior 
to leaving fields. 
Difficult to control weeds 
• Fields with difficult to control weeds should be planted in rotation with crops that 
allow the use of herbicides with an alternative mode of action or different 
management practices. 
• Difficult to control weeds may require sequential applications, such as a broad 
spectrum preemergence herbicide followed by one or more postemergence 
herbicide applications. Utilize herbicides containing different modes of action 
effective on the target weeds in sequential applications. 
Do not overuse the technology 
• Do not use more than two applications of this or any other herbicide with the 
same mode of action in a single growing season unless mixed with an herbicide 
with a different mode of action which provides overlapping spectrum for the 
difficult to control weeds.

Prefix Herbicide 
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Scout and inspect fields following application 
• Prevent an influx of weeds into the field by controlling weeds in field borders. 
• Scout fields after application to verify that the treatment was effective. 
• Suspected herbicide-resistant weeds may be identified by these indicators 
• Failure to control a weed species normally controlled by the herbicide at 
the dose applied, especially if control is achieved on adjacent weeds; 
• A spreading patch of non-controlled plants of a particular weed species; 
and 
• Surviving plants mixed with controlled individuals of the same species. 
• Report non-performance of this product to your Syngenta retailer, Syngenta 
representative, or call 1-866-Syngent(a) (866-796-4368). If resistance is 
suspected ensure weed escapes are controlled using an herbicide with an 
effective mode of action and/or use non-chemical means to prevent further seed 
production. 
Prevent weed escapes before, during, and after harvest 
• Do not allow weed escapes to produce seed or vegetative structures such as 
tubers or stolons which contribute to spread and survival. Consider harvest 
weed seed management and control weeds post-harvest to prevent seed 
production. 
 
SPRAY DRIFT MANAGEMENT 
 
MANDATORY SPRAY DRIFT MANAGEMENT 
Aerial Applications: 
 
x Do not release spray at a height greater than 10 ft above the vegetative 
canopy, unless a greater application height is necessary for pilot safety. 
x For applications prior to the emergence of crops and target weeds, applicators 
are required to select the nozzle and pressure that deliver coarse or coarser 
droplets (ASABE S641). 
x For all other applications, applicators are required to select the nozzle and 
pressure that deliver medium or coarser droplets (ASABE S641). 
x Do not apply when wind speeds exceed 15 miles per hour at the application 
site. If the wind speed is greater than 10 mph, the boom length must be 65% or 
less of the wingspan for fixed wing aircraft and 75% or less of the rotor 
diameter for helicopters. Otherwise, the boom length must be 75% or less of 
the wingspan for fixed-wing aircraft and 90% or less of the rotor diameter for 
helicopters.

Prefix Herbicide 
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x If the wind speed is 10 mph or less, applicators must use ½ swath 
displacement upwind at the downwind edge of the field. When the wind speed 
is 11-15 miles per hour, applicators must use 3/4 swath displacement upwind 
at the downwind edge of the field. 
x Nozzles must be oriented so the spray is directed toward the back of the 
aircraft. 
x Do not apply during temperature inversions. 
 
Ground Boom Applications: 
 
x User must only apply with the nozzle height recommended by the 
manufacturer, but no more than 3 feet above the ground or crop canopy. 
x For applications prior to the emergence of crops and target weeds, applicators 
are required to select the nozzle and pressure that deliver coarse or coarser 
droplets (ASABE S572). 
x For all other applications, applicators are required to select the nozzle and 
pressure that deliver medium or coarser droplets (ASABE S572). 
x Do not apply when wind speeds exceed 15 miles per hour at the application 
site. 
x Do not apply during temperature inversions. 
 
SPRAY DRIFT ADVISORIES 
 
THE APPLICATOR IS RESPONSIBLE FOR AVOIDING OFF-SITE SPRAY DRIFT. 
BE AWARE OF NEARBY NON-TARGET SITES AND ENVIRONMENTAL 
CONDITIONS. 
 
IMPORTANCE OF DROPLET SIZE 
An effective way to reduce spray drift is to apply large droplets. Use the largest droplets 
that provide target pest control. While applying larger droplets will reduce spray drift, the 
potential for drift will be greater if applications are made improperly or under unfavorable 
environmental conditions. 
Controlling Droplet Size – Ground Boom 
x Volume - Increasing the spray volume so that larger droplets are produced will 
reduce spray drift. Use the highest practical spray volume for the application. If a 
greater spray volume is needed, consider using a nozzle with a higher flow rate. 
x Pressure - Use the lowest spray pressure recommended for the nozzle to produce 
the target spray volume and droplet size. 
x Spray Nozzle - Use a spray nozzle that is designed for the intended application. 
Consider using nozzles designed to reduce drift. 
 
Controlling Droplet Size – Aircraft 
x Adjust Nozzles - Follow nozzle manufacturers recommendations for setting up 
nozzles. Generally, to reduce fine droplets, nozzles should be oriented parallel with 
the airflow in flight.

Prefix Herbicide 
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BOOM HEIGHT – Ground Boom 
x Use the lowest boom height that is compatible with the spray nozzles that will 
provide uniform coverage. For ground equipment, the boom should remain level with 
the crop and have minimal bounce. 
 
RELEASE HEIGHT - Aircraft 
x Higher release heights increase the potential for spray drift. 
 
SHIELDED SPRAYERS 
x Shielding the boom or individual nozzles can reduce spray drift. Consider using 
shielded sprayers. Verify that the shields are not interfering with the uniform 
deposition of the spray on the target area. 
 
TEMPERATURE AND HUMIDITY 
x When making applications in hot and dry conditions, use larger droplets to reduce 
effects of evaporation. 
 
TEMPERATURE INVERSIONS 
x Drift potential is high during a temperature inversion. Temperature inversions are 
characterized by increasing temperature with altitude and are common on nights 
with limited cloud cover and light to no wind. The presence of an inversion can be 
indicated by ground fog or by the movement of smoke from a ground source or an 
aircraft smoke generator. Smoke that layers and moves laterally in a concentrated 
cloud (under low wind conditions) indicates an inversion, while smoke that moves 
upward and rapidly dissipates indicates good vertical air mixing. Avoid applications 
during temperature inversions. 
 
WIND 
x Drift potential generally increases with wind speed. AVOID APPLICATIONS 
DURING GUSTY WIND CONDITIONS. 
 
x Applicators need to be familiar with local wind patterns and terrain that could affect 
spray drift. 
 
 
MIXING INSTRUCTIONS 
 
Prepare no more spray mixture than is needed for the immediate operation. Thoroughly 
clean the spray equipment before using Prefix Herbicide. Vigorous agitation is 
necessary to maintain uniformity of the spray mixture. Maintain maximum agitation 
throughout the spraying operation. Do not allow spray mixture to stand overnight in the 
spray tank. Flush the spray equipment thoroughly following each use and apply the 
rinsate to a previously treated area.

Prefix Herbicide 
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Application in Water or Fluid Fertilizers 
 
Prefix Herbicide Alone: Add ѿ of the required amount of water or fluid fertilizer to the 
spray or mixing tank. With the agitator running, add Prefix Herbicide into the spray tank. 
Continue agitation while adding the remainder of the water or fluid fertilizer. Begin 
application of the spray solution after the Prefix Herbicide has completely dispersed in 
the water or fluid fertilizer. Maintain agitation until all of the mixture has been applied. 
 
Prefix Herbicide + Tank Mixtures: Add ѿ of the required amount of water or fluid 
fertilizer to the mix tank. Start the agitator running before adding any tank mix partners. 
In general, tank mix partners should be added in this order: products packaged in 
water-soluble packaging, wettable powders, wettable granules (dry flowables), liquid 
flowables, liquids such as Prefix Herbicide, and emulsifiable concentrates. Always allow 
each tank mix partner to become fully dispersed before adding the next product. 
Provide sufficient agitation while adding the remainder of the water. Maintain agitation 
until all of the mixture has been applied. 
 
Notes: (1) When using Prefix Herbicide in tank mixtures, all products in water-soluble 
packaging should be added to the tank and mixed with plain water before any other tank 
mix partner, including Prefix Herbicide. Allow the water-soluble packaging to completely 
dissolve and the product(s) to completely disperse before adding any other tank mix 
partner to the tank. (2) Water-soluble packets will not properly dissolve in most spray 
solutions that contain fluid fertilizers. 
 
Prefix Herbicide is compatible with most common tank mix partners. However, the 
physical compatibility of Prefix Herbicide with tank mix partners should be tested before 
use. To determine the physical compatibility of Prefix Herbicide with other products, 
use a jar test, as described below. 
 
Precaution: Do not use nitrogen solutions or fluid fertilizers as a complete or partial 
spray carrier when applying Prefix Herbicide as a postemergence application to 
soybeans as these combinations may cause crop injury. 
 
It is the pesticide user’s responsibility to ensure that all products are registered for the 
intended use. Read and follow the applicable restrictions and limitations and directions 
for use on all product labels involved in tank mixing. Users must follow the most 
restrictive directions for use and precautionary statements of each product in the tank 
mixture. 
 
Tank-Mix Compatibility Test 
 
A jar test is recommended before tank mixing to ensure compatibility of Prefix Herbicide 
with other pesticides. The following test assumes a spray volume of 25 gal/A. For other 
spray volumes, make appropriate changes in the ingredients.

Prefix Herbicide 
Page 12 
 
Note: Nitrogen solutions or complete fluid fertilizers may replace all or part of the water 
in the spray for preplant surface, preplant incorporated, or preemergence applications 
only. Because liquid fertilizers vary, even within the same analysis, always check 
compatibility with pesticide(s) before use. Incompatibility of tank mixtures is more 
common with suspensions of fertilizer and pesticides. 
 
Test Procedure 
 
1. Add 1.0 pt of carrier (fertilizer or water) to each of 2 one qt jars with tight lids. 
Note: Use the same source of water that will be used for the tank mix and 
conduct the test at the temperature the tank mix will be applied. 
 
2. To one of the jars, add ¼ tsp or 1.2 milliliters of a compatibility agent approved 
for this use, such as Compex® or Unite® (¼ tsp is equivalent to 2.0 pt/100 gal 
spray). Shake or stir gently to mix. 
 
3. To both jars, add the appropriate amount of pesticide(s) in their relative 
proportions based on label rates. If more than one pesticide is used, add them 
separately with dry pesticides first, flowables next, and emulsifiable concentrates 
last. After each addition, shake or stir gently to thoroughly mix. 
 
4. After adding all ingredients, put lids on and tighten, and invert each jar ten times 
to mix. Let the mixtures stand 15-30 minutes and then look for separation, large 
flakes, precipitates, gels, heavy oily film on the jar, or other signs of 
incompatibility. Determine if the compatibility agent is needed in the spray 
mixture by comparing the two jars. If either mixture separates, but can be 
remixed readily, the mixture can be sprayed as long as good agitation is used. If 
the mixtures are incompatible, test the following methods of improving 
compatibility: (a) Slurry the dry pesticide(s) in water before addition, or (b) add ½ 
the compatibility agent to the fertilizer or water and the other ½ to the 
emulsifiable concentrate or flowable pesticide before addition to the mixture. If 
incompatibility is still observed, do not use the mixture. 
 
5. After compatibility testing is complete, dispose of any pesticide wastes in 
accordance with the Storage and Disposal section in this label.

Prefix Herbicide 
Page 13 
 
APPLICATION INSTRUCTIONS 
 
Activation 
 
A small amount of soil moisture is required to activate Prefix Herbicide following 
application. In areas of low rainfall, a preemergence application to dry soil should be 
followed with light irrigation of 0.25-0.5 inch of water. As with many surface-applied 
herbicides, weed control and crop tolerance may vary with rainfall and/or soil texture. If 
rainfall or irrigation within 7-10 days does not occur, cultivate uniformly with shallow 
tilling equipment such as a rotary hoe that will not damage soybeans. 
 
Ground Application: Apply Prefix Herbicide alone or in tank mixtures by ground 
equipment in a minimum of 10 gallons of spray mixture per acre, unless otherwise 
specified. {Optional} [For certain ground application equipment approved by Syngenta, 
apply in a minimum of 2 gallons of spray mixture per acre. Contact your local Syngenta 
representative for a list of approved equipment.] 
 
Use sprayers that provide accurate and uniform application. Calibrate the sprayer 
before use at the beginning of the season. For Prefix Herbicide tank mixtures with 
wettable powder or dry flowable formulations, use screens and strainers no finer than 
50-mesh. 
 
Band Applications 
 
Calculate the amount of herbicide needed for band treatment by the formula: 
 
Band width in inches 
X broadcast rate = amount needed 
Row width in inches per acre per acre of field 
 
Chemigation: Do not apply Prefix Herbicide through any type of irrigation system. 
 
Aerial Application: Apply Prefix Herbicide in water using a minimum spray volume of 
5 gal/A. Avoid application under conditions where uniform coverage cannot be obtained 
or where excessive spray drift may occur. Make applications at a maximum height of 
10 ft above the soybeans with low-drift nozzles at a maximum pressure of 40 psi. 
 
Avoid application to humans or animals. Flagmen and loaders should avoid inhalation 
of spray mist and prolonged contact with skin. 
 
Sensitive Areas 
 
Prefix Herbicide should only be applied when the potential for drift to adjacent sensitive 
areas (e.g., residential areas, bodies of water, known habitat for threatened or 
endangered species, non-target crops) is minimal (e.g., when wind is blowing away 
from the sensitive areas).

Prefix Herbicide 
Page 14 
 
Cleaning Equipment After Application 
 
Because some crops, other than soybeans, are sensitive to low rates of Prefix 
Herbicide, special attention must be given to cleaning equipment before spraying a crop 
other than those registered for use and on this label. Mix only as much spray solution 
as needed. Immediately after spraying, clean equipment thoroughly using the following 
procedure: 
 
1. Flush tank, hoses, boom, and nozzles with clean water. 
 
2. Prepare a cleaning solution of one gal of household ammonia per 50 gal of 
water. Many commercial spray tank cleaners may be used as well. Consult your 
Syngenta representative for a partial listing of approved tank cleaners and more 
information about proper tank cleaning procedures. Do not use chlorine-based 
cleaners such as Clorox®. 
 
3. When available, use a pressure washer to clean the inside of the spray tank with 
this solution. Take care to wash all parts of the tank, including the inside top 
surface. Completely fill the sprayer with the cleaning solution to ensure contact 
of the cleaning solution with all internal surfaces of the tank and plumbing. Start 
agitation in the sprayer and thoroughly re-circulate the cleaning solution for at 
least 15 minutes. All visible deposits must be removed from the spraying 
system. 
 
4. Flush hoses, spray lines, and nozzles for at least one minute with the cleaning 
solution. 
 
5. Do not apply directly to water, to areas where surface water is present, or to 
intertidal areas below the mean water mark. Do not contaminate water when 
disposing of equipment wash water or rinsate. Do not apply when weather 
conditions favor drift from target area. 
 
6. Repeat steps 2-5. 
 
7. Remove nozzles, screens, diaphragm check valves and strainers and clean 
separately in the ammonia cleaning solution after completing the above 
procedures. 
 
8. Rinse the complete spraying system with clean water. 
 
RESTRICTIONS 
 
x A maximum of 3 pt of Prefix Herbicide (or a maximum of 0.375 lb ai/A of 
fomesafen from any product containing fomesafen) may be applied per acre per 
year in Region 1 (see Regional Use Map).

Prefix Herbicide 
Page 15 
 
x A maximum of 3 pt of Prefix Herbicide (or a maximum of 0.375 lb ai/A of 
fomesafen from any product containing fomesafen) may be applied per acre in 
ALTERNATE years in Region 2 (see Regional Use Map). 
 
x A maximum of 2.5 pt of Prefix Herbicide (or a maximum of 0.313 lb ai/A of 
fomesafen from any product containing fomesafen) may be applied per acre in 
ALTERNATE years in Region 3 (see Regional Use Map). 
 
x A maximum of 2 pt of Prefix Herbicide (or a maximum of 0.25 lb ai/A of fomesafen 
from any product containing fomesafen) may be applied per acre in ALTERNATE 
years in Region 4 (see Regional Use Map). 
 
x A maximum of 2 pt of Prefix Herbicide (or a maximum of 0.25 lb ai/A of fomesafen 
from any product containing fomesafen) may be applied per acre in ALTERNATE 
years in Region 4a (see Regional Use Map). 
 
o Apply only to soybeans in Region 4a. 
 
x Do not make a Prefix Herbicide application later than June 10th20th. 
 
o Cumulative rainfall plus overhead irrigation must total 15 inches from the period 
of Prefix Herbicide application to soybean crop maturity to allow planting of rotational 
crops listed in this label (refer to Crop Rotation Intervals Following Prefix Herbicide 
Application section). If the soybean crop is lost or the required cumulative rainfall plus 
irrigation is not received as outlined above, plant only soybeans the following growing 
season. 
 
x Do not graze treated areas or harvest for forage or hay. 
 
x To prevent off-site movement due to runoff or wind erosion: 
x Do not treat powdery dry or light sand soils when conditions are favorable for wind 
erosion. Under these conditions, the soil surface should first be settled by rainfall 
or irrigation. 
x Do not apply to impervious substrates, such as paved or highly compacted 
surfaces. 
x Do not use tailwater from the first flood or furrow irrigation of treated fields to treat 
non-target crops, unless at least ½ inch of rainfall has occurred between 
application and the first irrigation. 
 
 
PRECAUTIONS 
 
x Avoid overlapping spray swaths, as injury may occur to rotational crops.

Prefix Herbicide 
Page 16 
 
 
PREFIX HERBICIDE - USE RATES AND WEEDS CONTROLLED 
 
REFER TO MAP FOR DEFINITION OF SPECIFIED 
GEOGRAPHIC REGIONS 
 
PREFIX HERBICIDE REGIONAL USE MAP

Prefix Herbicide 
Page 17 
 
REGION 1 
(Maximum Rate 3 pt/A (0.375 lb ai/A of fomesafen) per year) 
 
 
 
Includes the following states or portion of states where Prefix Herbicide may be 
applied: 
Region 1 
Alabama All areas. 
Arkansas All areas. 
Florida All areas except Miami-Dade County. 
Georgia All areas. 
Louisiana All areas. 
Mississippi All areas. 
Missouri Counties of Bollinger, Butler, Cape Giradeau, Dunklin, 
Madison, Mississippi, New Madrid, Pemiscot, Perry, 
Riple
y, Scott, Stoddard and Wayne. 
North Carolina All areas. 
Oklahoma All areas east of U.S. Highway 75 and east of Indian 
Nation Parkway. 
South Carolina All areas. 
Tennessee All areas. 
Texas All areas east of U. S. Highway 77 to State Road 239 
including all of Calhoun County. 
Not For Use in 
Miami-Dade County, FL

Prefix Herbicide 
Page 18 
 
REGION 2 
(Maximum Rate 3 pt/A (0.375 lb ai/A of fomesafen), alternate years) 
 
 
 
 
Includes the following states or portion of states where Prefix Herbicide may be 
applied: 
Region 2 
Delaware All areas. 
Illinois All areas south of Interstate 70. 
Indiana All areas south of Interstate 70. 
Kentucky All areas. 
Maryland All areas. 
Ohio All areas south of Interstate 70. 
Pennsylvania All areas south of Interstate 80 to the intersection of 
U.S. Highway 15 and east of U.S. Highway 15 and U.S. 
Hi
ghway 522. 
Virginia All areas. 
West Virginia All areas.

Prefix Herbicide 
Page 19 
 
REGION 3 
(Maximum Rate 2.5 pt/A (0.313 lb ai/A of fomesafen), alternate years) 
 
 
 
Includes the following states or portion of states where Prefix Herbicide may be 
applied: 
Region 3 
Connecticut All areas. 
Illinois All areas north of Interstate 70. 
Indiana All areas north of Interstate 70. 
Iowa All areas. 
Maine All areas. 
Massachusetts All areas. 
Missouri All areas except those listed in Region 1. 
New 
Hampshire 
All areas. 
New Jersey All areas. 
New York All areas. 
Ohio All areas north of Interstate 70. 
Pennsylvania All areas except those listed in Region 2 
Rhode Island All areas. 
Vermont All areas. 
Wisconsin All areas south of U.S. Highway 18 between Prairie Du 
Chien and Madison, and south of Interstate 94 
between Madison and Milwaukee.

Prefix Herbicide 
Page 20 
 
REGION 4 
(Maximum Rate 2 pt/A (0.25 lb ai/A of fomesafen), alternate years) 
 
 
 
Includes the following states or portion of states where Prefix Herbicide may be 
applied: 
Region 4 
Kansas All counties east of or intersected by U.S. Highway 281. 
Michigan Southern Peninsula. 
Minnesota All areas south of Interstate 94. 
Nebraska All counties east of or intersected by U.S. Highway 281. 
North Dakota All areas east of Interstate 29 from Fargo south to the 
South Dakota state line. 
South Dakota All areas east of Interstate 29 from the North Dakota state 
line to Watertown, all areas east of Highway 81 from 
Watertown to Madison and all areas east and south of 
State Road 34 and U.S. Highway 281 to the Nebraska 
state line. 
Wisconsin All areas south of Interstate 94 (except those in Region 3) 
from Minnesota state line to Eau Claire and south of U.S. 
Highway 29 from Eau Claire to Green Bay plus Barron, 
Burnett, Chippewa, Clark, Door, Dunn, Eau Claire, 
Kewaunee, Langlade, Lincoln, Marathon, Marinette, 
Menominee, Oconto, Polk, Price, Rusk, Shawano, and St. 
Croix, Taylor, and Washburn counties. The following 
counties are excluded: Adams, Marquette, Portage, 
Waupaca, Waushara and Wood.

Prefix Herbicide 
Page 21 
 
REGION 4a 
(Maximum Rate 2 pt/A (0.25 lb ai/A of fomesafen), alternate years*) 
 
 
 
 
Includes the following states or portion of states where Prefix Herbicide may be 
applied: 
Region 4a 
Kansas All areas west of U.S. Highway 281 to the Colorado state 
line. 
Nebraska All areas that intersect west of U.S. Highway 281 and east 
of U.S. Highway 83. 
 
*Note: Refer to the Restrictions section for additional requirements that must be 
followed to use Prefix Herbicide in Region 4a. Refer to the Precautions section 
for information for the use of Prefix Herbicide in Region 4a.

Prefix Herbicide 
Page 22 
 
Replanting 
 
If replanting is necessary in fields previously treated with Prefix Herbicide, the field may 
be replanted to soybeans. During planting, a minimum of tillage is recommended. Do 
not apply a second application of Prefix Herbicide or any product that contains 
metolachlor, fomesafen, or S-metolachlor as crop injury or illegal residues may occur in 
harvested soybeans. 
 
Rotational Crops 
 
Do not rotate to food or feed crops other than those listed below. 
 
Table 1: Crop Rotation Intervals Following Prefix Herbicide Application
 
 
Rotational Crops 
Planting Time From Last 
Prefix Herbicide Application 
Bean, Dry 
Bean, Snap 
Soybean 
So
ybean, Succulent (edamame) 
0 months 
Cotton 
Potato 1 month 
Bean, Lima 
Pea, Succulent 
Peanut 
4 months 
Barley 
Oat 
Rye 
Wheat 
4.5 months 
Corn, Field 
Corn, Seed 
Corn, Sweet
5 
Pepper (transplanted)1 
Popcorn4 
Pumpkin2 
Rice 
Tomato (transplanted)
1 
Watermelon2 
10 months 
Bean, Succulent (other than edamame, snap bean and 
lima bean) 
Cantaloupe2 
Cucumber2 
Edible-podded beans and peas not otherwise specified in 
this table 
Eggplant 
Pea, Dried 
12 months

Prefix Herbicide 
Page 23 
 
Rotational Crops 
Planting Time From Last 
Prefix Herbicide Application 
Pepper (direct seeded) 
Squash, Summer 
Squash, Winter
2 
Sunflower 
Sweet Potato 
Tomato 
(direct seeded) 
Sorghum3 18 months 
All other crops not listed above 18 months 
14 months in Region 1 
28 months in Region 1 
310 months in Region 1 
412 months in the states of Ohio, Kentucky, Illinois, Indiana, Iowa, Region 4 and Region 
4a when applied at 2 pints per acre or more. 
518 months in the states of Connecticut, Maine, Massachusetts, New Hampshire, New 
York, Rhode Island, and Vermont. 
 
Cover crops for soil building or erosion control may be planted any time, but do not 
graze or harvest for food or feed. Stand reductions may occur in some areas.
 
 
Do not graze rotated small grain crops or harvest forage or straw for livestock. 
 
Cover Crops 
 
A cover crop can be an important tool for the overall farm cropping system. Cover 
crops are planted for conservation purposes, soil erosion control, soil health 
improvement, water quality improvement and weed management. A cover crop can be 
a single crop or a combination of crops, including grasses and/or broadleaf crops. 
After harvest of a Prefix Herbicide treated crop, planting of a cover crop is allowed 
provided the cover crop is not grazed or fed to livestock nor harvested for food. 
Terminate the cover crop through natural causes such as frost or intentional termination 
by herbicide application, crimping, rolling, tillage or cutting. All possible cover crops or 
cover crop combinations have not been tested for tolerance to this product. Before 
planting the cover crop, determine the level of tolerance for the intended cover crops by 
conducting a field bioassay. Refer to the Field Bioassay for Cover Crops section for 
instructions on how to conduct a field bioassay. 
 
Field Bioassay for Cover Crops 
 
A field bioassay is a method of determining if herbicide residues are present in the soil 
at concentrations high enough to adversely affect crop growth. Conduct the field 
bioassay by planting several strips of the desired cover crop across the field which has 
been previously treated with Prefix Herbicide. Plant the cover crop strips perpendicular 
to the direction of the product application. Locate the strips so that all the different field 
conditions are encountered, including differences in field terrain, soil texture, organic

Prefix Herbicide 
Page 24 
 
matter, pH, and drainage. If the cover crop does not show adverse effects such as crop 
injury and/or stand reduction, the field can be planted to this cover crop. If injury and/or 
stand reduction are visible, wait two to four weeks for further herbicide degradation to 
occur and repeat the bioassay. Alternatively, select a different cover crop and repeat 
the bioassay. Only plant cover crops that show acceptable tolerance in the field 
bioassay. 
 
Rate Ranges 
 
Where a rate range is within a soil texture/organic matter classification, use a lower rate 
on soils that are relatively coarse-textured and/or low in organic matter. Use a higher 
rate on soils that are relatively fine-textured and/or high in organic matter. 
 
Prefix Herbicide, when applied as directed, will control or partially control the following 
weeds.

Prefix Herbicide 
Page 25 
 
Table 2: Weeds Controlled or Partially Controlled* by Prefix Herbicide 
 
Weed 
C = Control 
PC = Partial 
Control Weed 
C = Control 
PC = Partial 
Control 
Annual Grasses 
Barnyardgrass C Jun glerice C 
Crabgrass spp. C Panicum, fall C 
Crowfootgrass C Panicum, Texas PC 
Cupgrass, prairie C Red rice PC 
Cupgrass, southwestern C Si gnalgrass, broadleaf C 
Foxtail spp. C Sandbur spp. PC 
Goosegrass C Shattercane PC 
Johnsongrass, seedling PC Witch grass C 
 
Broadleaves 
Carpetweed C Purslane, common C 
Cocklebur, common PC Pusle y, Florida C 
Ecliptia C Ra gweed, common C 
Galinsoga spp. C Ra gweed, giant PC 
Horseweed/marestail PC Redweed C 
Jimsonweed PC Sida, prickl y/teaweed PC 
Lambsquarters, common C Smartweed, lad ysthumb C 
Morningglory spp. PC Smartweed, Penns ylvania C 
Nightshade, eastern black C Spur ge, spotted C 
Nightshade, hairy PC Starbur, bristl y C 
Pennycress, field C Sunflower, common PC 
Pepperweed, Virginia C Velvetleaf PC 
Pigweed spp. C Waterhemp spp. C 
Poinsettia, wild C 
 
Sedges 
Nutsedge, yellow PC 
 
*Partially controlled means significant activity, but not always at a level considered 
acceptable for commercial weed control. 
 
 
COTTON 
 
Post-Directed Application 
 
Apply Prefix Herbicide in emerged cotton as a post-directed treatment using precision 
post-directed, hooded or shielded application equipment to provide complete coverage 
of emerged weeds. Apply Prefix Herbicide at 2-2.33 pints per acre. Prefix Herbicide

Prefix Herbicide 
Page 26 
 
will control or partially control certain emerged broadleaf weeds such as hemp 
sesbania, waterhemp, pigweed species and morningglory species. Apply when 
broadleaf weeds have 2-4 true leaves in a minimum of 10 gallons spray solution per 
acre. Prefix Herbicide should be applied with a non-ionic surfactant at 0.25 to 0.5% v/v 
or crop oil concentrate at 1% v/v to emerged weeds if applied alone or in a tank mix with 
products that do not contain a built-in adjuvant. Do not add liquid nitrogen (28% or 
similar) to Prefix Herbicide, or Prefix Herbicide tank mixes in cotton. Refer to Table 2 
for weeds controlled or partially controlled with soil activation of Prefix Herbicide if 
rainfall or irrigation occurs within 7-10 days after application. 
 
To broaden the weed control spectrum, Prefix Herbicide may be tank mixed with other 
labeled post-directed herbicides such as Caparol, DSMA, Direx, Envoke®, Karmex, 
Layby™ Pro, MSMA, Suprend® or glyphosate (such as Roundup® brands for use in 
glyphosate-resistant cotton only). Refer to the tank-mix partner label for precautionary 
statements, restrictions, rates and a list of weeds controlled. 
 
Cotton foliage is not tolerant to Prefix Herbicide applications. Avoid contact to cotton 
foliage and stems that are not fully barked as unacceptable injury will occur. Application 
equipment should be calibrated (spray pressure, nozzle type and configuration, and 
orifice size) to deliver medium or coarser spray droplets contacting green cotton stems 
and foliage. 
 
Post-Directed Application Timing in Cotton 
 
Prefix Herbicide may be applied to cotton at least 6 inches in height through layby as a 
post-directed application. All post-directed applications should avoid spray contact with 
any green non-barked parts of the cotton plant or foliage as unacceptable injury will 
occur. Follow the application timing recommendations below for post-directed 
applications in cotton. 
 
Shielded and Hooded Applications 
 
Make a precision post-directed Prefix Herbicide application to the base of the 
cotton plant avoiding contact with the cotton stem or foliage when cotton is at 
least 6 inches in height to avoid cotton injury. Use only hooded or shielded spray 
equipment to apply Prefix Herbicide in cotton that is at least to 6 inches in height. 
Adjust nozzles to provide full coverage of emerged target weeds. 
 
Layby Applications 
 
Make a post-directed Prefix Herbicide application to the base of the cotton plant 
avoiding contact with any non-barked portion of the cotton plant or foliage. Use 
precision post-directed equipment or hooded or shielded sprayers on cotton that 
has developed a minimum of 4 inches of brown bark through layby. Application 
equipment should be configured to provide full coverage of emerged target 
weeds.

Prefix Herbicide 
Page 27 
 
 
Restrictions - Cotton 
 
x Do not apply Prefix Herbicide later than 80 days before harvest. 
 
x Do not exceed 2.33 pt/A of Prefix Herbicide in a single application. 
 
x Do not apply more than 2.33 pints per acre of Prefix Herbicide in any year and also 
adhere to the maximum rate that may be applied in each geographic region (refer to 
the Prefix Herbicide Regional Use Map). 
 
x Do not exceed 2.48 lb ai/A per year of S-metolachlor -containing products. 
 
x Do not graze or feed forage or fodder from cotton to livestock. 
 
SOYBEAN [(NOT FOR USE IN CALIFORNIA)] 
 
PREFIX HERBICIDE FOUNDATION TREATMENT FOR PLANNED TWO-PASS 
WEED CONTROL PROGRAMS IN ALL TILLAGE SYSTEMS 
 
Prefix Herbicide at 2 pt/A may be applied as a preemergence application on all soils to 
reduce competition from weeds for a period of up to 5 weeks when followed by a 
planned postemergence herbicide application in conventional or herbicide-resistant 
soybeans. Refer to Table 2 for weeds controlled or partially controlled. For the 
postemergence herbicide application, consult the selected postemergence herbicide 
manufacturer's label for weeds controlled, optimum weed size, application rate, 
additional use directions, precautions, and limitations before use. 
 
Preplant Surface Applied: For minimum-tillage or no-tillage systems only, Prefix 
Herbicide may be applied at 2 pt/A prior to soybean planting. If weeds are present at 
the time of treatment, apply Prefix Herbicide in a tank mixture with a burndown 
herbicide. To the extent possible, minimize movement of treated soil out of the row or 
untreated soil to the surface during planting, or weed control will be diminished. Follow 
with a postemergence herbicide applied at the labeled rate and within the specific 
growth stage for soybeans and weed spectrum. Recommended postemergence 
treatments include any product or combination of products labeled to control the specific 
weeds remaining in the field. 
 
Preplant Incorporated: Apply Prefix Herbicide at 2 pt/A in conventional tillage systems 
where incorporation into the top 2 inches of soil occurs within 7 days after application 
using a finishing disk, harrow, rolling cultivator or similar implement capable of providing 
uniform 2-inch incorporation. Follow with a postemergence herbicide applied at the 
labeled rate and within the specific growth stage for soybeans and weed spectrum. 
Recommended postemergence treatments include any product or combination of 
products labeled to control the specific weeds remaining in the field.

Prefix Herbicide 
Page 28 
 
Preemergence: Apply Prefix Herbicide at 2 pt/A during planting (behind the planter), or 
after planting, but before weeds or soybeans emerge in conventional, conservation, or 
no-till systems. If weeds are present at the time of treatment, apply Prefix Herbicide in a 
tank mixture with a burndown herbicide (such as, paraquat or glyphosate brands). 
Follow with a postemergence herbicide applied at the labeled rate and within the 
specific growth stage for soybeans and weed spectrum. Recommended 
postemergence treatments include any product or combination of products labeled to 
control the specific weeds remaining in the field. 
 
PREFIX HERBICIDE IN CONVENTIONAL TILLAGE SYSTEMS 
 
For conventional tillage systems, Prefix Herbicide may be applied preplant incorporated 
or preemergence for control or partial control of weeds listed in Table 2. Prefix 
Herbicide may be applied alone, or in tank mix or followed sequentially with 
postemergence herbicides to broaden the weed control spectrum or control newly 
emerged weeds. Refer to Table 3 for Prefix Herbicide rates. 
 
Preplant Incorporated Application 
 
Incorporate Prefix Herbicide uniformly into the top 2 inches of soil within 7 days after 
application and before planting using a disk, field cultivator, rolling cultivator, or similar 
implement. Apply Prefix Herbicide preplant incorporated if furrow irrigation is used or 
when a period of dry weather after application is expected. 
 
Preemergence Application 
 
Apply during planting (behind the planter), or after planting, but before weeds or 
soybeans emerge. Dry weather following preemergence application of Prefix Herbicide 
may reduce effectiveness. If weeds develop, cultivate uniformly with shallow tilling 
equipment such as a rotary hoe that will not damage soybeans.

Prefix Herbicide 
Page 29 
 
Table 3: Prefix Herbicide Use Rates - Conventional Tillage Systems (Broadcast 
Rates) 
 
 Pints/A 
 
Soil Texture 
 
Regions 
0.5 to 3% 
Organic Matter 
Over 3% 
Organic Matter 
COARSE (Sand, loamy sand, sandy 1, 2 2 2-2.25 
loam) 3 2 2-2.25 
 4, 4a 2 2 
MEDIUM (Loam, silt loam, silt) 1, 2 2.25-2.5 2.5-2.75 
 3 2-2.25 2.25-2.5 
 4, 4a 2 2 
FINE (Sandy clay loam, sandy clay, 1, 2 2.75-3 2.75-3 
silty clay, silty clay loam, clay, 3 2.5* 2.5* 
clay loam) 4, 4a 2* 2* 
*If weeds emerge before full canopy closure, apply an appropriate postemergence 
product. 
 
PREFIX HERBICIDE USE RATES FOR REDUCED AND NO-TILL SYSTEMS 
 
Preplant Surface and Preemergence Application 
 
Prefix Herbicide may be used in reduced-till and no-till systems. Prefix Herbicide may 
be applied up to 15 days before planting or preemergence, but before soybean 
emergence. For control or partial control of weeds listed in Table 2, use the high end of 
the rate range for Prefix Herbicide applications made 15 days before planting. Refer to 
Table 4 for Prefix Herbicide rates. If weeds are present at time of application, burndown 
herbicides may be tank mixed with Prefix Herbicide (see Burndown Weed Control 
section). Prefix Herbicide may be followed sequentially with postemergence herbicides 
to broaden the weed control spectrum or control newly emerged weeds. 
 
Table 4: Prefix Herbicide Use Rates for Reduced-Till and No-Till Systems 
(Broadcast Rates) 
 
Soil Texture Re
gions Pints/A 1 
COARSE (Sand, loamy sand, sandy loam) 1, 2 2-2.5 
 3 2-2.25 
 4, 4a 2* 
MEDIUM (Loam, silt loam, silt, sandy clay, 1, 2 2.5-2.75 
sandy clay loam) 3 2.25-2.5 
 4, 4a 2* 
FINE (Sandy clay loam, sandy clay, silty clay, 1, 2 2.75-3 
silty clay loam, clay, clay loam) 3 2.5* 
 4, 4a 2* 
*If weeds emerge before full canopy closure, apply an appropriate postemergence 
product.

Prefix Herbicide 
Page 30 
 
1Use the lower rate range for low residue level or soils with less than 3% organic matter. 
Use the higher rate range for high residue level or soils with greater than 3% organic 
matter. 
 
BURNDOWN WEED CONTROL 
 
Prefix Herbicide can be used as part of a burndown herbicide program for control of 
existing vegetation prior to soybean planting and/or emergence in conservation tillage 
(reduced-tillage/no-till systems). Prefix Herbicide may be tank mixed with 2,4-D, 
dicamba, paraquat, fluazifop-P-butyl, fenoxaprop-P-ethyl, glyphosate brands, 
sethoxydim, or clethodim for control of emerged weeds prior to soybean planting or crop 
emergence. Refer to the tank mix product labels for specific rates, use directions, 
precautions, restrictions and limitations. 
 
HERBICIDES THAT MAY BE APPLIED POSTEMERGENCE FOLLOWING PREFIX 
HERBICIDE 
 
If required, application of Prefix Herbicide alone or in tank mixture may be followed by 
an application of a postemergence herbicide to provide additional control of certain 
weeds. Postemergence herbicide applications can be made with, but are not limited to 
the products listed below: 
 
Aim® 
Arrow® 
Assure® II 
Basagran® 
Classic® 
Cobra® 
Extreme®
1 
FirstRate® 
Fusilade DX 
Fusion 
Glyphosate
1 
Harmony® GT XP 
Liberty®
2 
Poast® 
Poast Plus 
Pursuit® 
Raptor® 
Raptor® 
Resource® 
Scepter® 
Select 
Synchrony® STS® 
Synchrony® XP 
Ultra Blazer® 
1 Glyphosate-resistant soybeans only. 
2 Glufosinate-resistant soybeans only. 
 
Refer to the individual product labels for use directions, use rates, and special 
precautions/restrictions. 
 
Restrictions 
 
x Do not apply more than the maximum rates and number of applications of Prefix 
Herbicide to soybeans in each geographic region (refer to the Prefix Herbicide 
Regional Use Map). 
x Do not exceed 3.71 lb ai/A/year of S-metolachlor- containing products 
x Refer to Prefix Herbicide Regional Use Map for the maximum rate of Prefix 
Herbicide (or other fomesafen- containing products) that may be applied in each 
geographic region.

Prefix Herbicide 
Page 31 
 
 
POSTEMERGENCE APPLICATION 
 
Prefix Herbicide may be applied at 2-2.33 pt/A as an early postemergence application in 
soybeans. Necrotic spotting, bronzing, crinkling or curling of soybean leaves may occur 
following postemergence application, but soybeans soon outgrow these effects and 
develop normally. Refer to Table 2 for weeds controlled or partially controlled with soil 
activation of Prefix Herbicide if rainfall or irrigation occurs within 7-10 days after 
postemergence application. Prefix Herbicide alone may control or partially control 
certain emerged broadleaf weeds, however, for broad spectrum control, tank mix Prefix 
Herbicide with glyphosate (such as Roundup brands) in glyphosate-resistant soybeans 
only. Add nonionic surfactant (NIS) containing at least 75% surface- active agent, at 
0.25% v/v to the final spray volume if Prefix Herbicide is applied alone or tank mixed 
with glyphosate products that do not contain a built-in adjuvant. The use of crop oil 
concentrate (COC) is not advised when applying Prefix Herbicide postemergence as 
these spray adjuvants may increase soybean injury. 
 
Tank Mixtures for Postemergence Applications in Soybeans: 
 
Prefix Herbicide may be tank mixed with, but is not limited to the following 
postemergence herbicides: 
 
Fusilade DX 
Fusion 
Glyphosate (Glyphosate-resistant soybeans only) 
Glufosinate (Glufosinate-resistant soybeans only) 
 
Tank mixes may cause necrotic spotting, bronzing, crinkling or curling of soybean 
leaves that are present at the time of the postemergence application. 
 
Prefix Herbicide may be tank mixed with the following insecticide: 
 
Karate® Insecticide with Zeon Technology 
 
Refer to this label and the labels of the tank mix partners for application methods and 
timings, precautionary statements, restrictions, rates, and weeds or insects controlled. 
 
Restrictions for Postemergence Application to Soybeans 
 
x Apply only in water as the carrier for postemergence applications. 
 
x Do not use Prefix Herbicide postemergence on soybeans that are under stress 
including but not limited to that caused by drought, insect, disease, or injury from 
cultivation. 
 
x Do not exceed 2.33 pt/A/year of Prefix Herbicide in a single postemergence

Prefix Herbicide 
Page 32 
 
application. 
 
x Do not exceed 3.0 pt/A of Prefix Herbicide per year. Refer to Regional Use Map for 
maximum rate that may be applied within a specific region. 
 
x Do not exceed 3.71 lb ai/A per year of S-metolachlor -containing product. 
 
x Make postemergence applications at least 75 days before harvest. 
 
x Do not graze or feed treated forage or hay from soybeans to livestock following a 
postemergence application of Prefix Herbicide. 
 
Tank-Mix Partner Table 
Product Name EPA Registration 
Number 
Active Ingredient(s) 
2,4-D LVE Various brands 2,4-D 
Aim® EC 279-3241 carfentrazone-ethyl 
Arrow® 2 EC 66222-60 clethodim 
Assure® II 353-541 quizalofop p-ethyl 
Basagran® 7969-112 bentazon 
Classic™ 353-436 chlorimuron ethyl 
Cobra 59639-34 lactofen 
Direx® 66222-54 diuron 
Extreme® 241-405 glyphosate + imazethapyr 
FirstRate® 62719-275 cloransulam-methyl 
Fusilade® DX 100-1070 fluazifop-p-butyl 
Fusion ® 100-1059 fluazifop-p-butyl + fenoxaprop-p-ethyl 
Harmony® GT XP 279-9577 thifensulfuron methyl 
Karmex® 66222-51 diuron 
Liberty® 264-829 glufosinate-ammonium 
MSMA 19713-42 MSMA 
Poast® 7969-58 sethoxydim 
Poast Plus® 7969-88 sethoxydim 
Pursuit® 241-310 imazethapyr 
Raptor® 241-379 imazamox 
Resource® 59639-82 flumiclorac pentyl ester 
Roundup Brands Various brands glyphosate 
Scepter® 241-306 imazaquin 
Select® 59639-3 clethodim 
Synchrony® XP 352-648 thifensulfuron + chlorimuron ethyl 
Ultra Blazer 70506-60 acifluorfen

Prefix Herbicide 
Page 33 
 
 
STORAGE AND DISPOSAL 
 
Do not contaminate water, food, or feed by storage or disposal. 
 
Pesticide Storage 
 
This product will freeze at a temperature of approximately 5ºF, but upon warming will 
thaw out to a fully homogeneous product. 
 
Pesticide Disposal 
 
Open dumping is prohibited. Wastes resulting from the use of this product are toxic. 
Improper disposal of unused pesticide, spray mixture, or rinsate is a violation of 
federal law. Pesticide, spray mixture, or rinsate that cannot be used according to 
label instructions must be disposed of according to federal, state, or local procedures. 
For guidance in proper disposal methods, contact your State Pesticide or 
Environmental Control Agency, or the Hazardous Waste representative at the nearest 
EPA Regional Office. 
 
Container Handling [less than or equal to 5 gallons] 
 
Non-refillable container. Do not reuse or refill this container. Triple rinse container 
(or equivalent) promptly after emptying. Triple rinse as follows: empty the remaining 
contents into application equipment or a mix tank and drain for 10 seconds after the 
flow begins to drip. Fill the container ¼ full with water and recap. Shake for 10 
seconds. Pour rinsate into application equipment or a mix tank or store rinsate for 
later use or disposal. Drain for 10 seconds after the flow begins to drip. Repeat this 
procedure two more times. Then offer for recycling if available or puncture and 
dispose of in a sanitary landfill, or by incineration, or by other procedures approved by 
state and local authorities. 
 
Container Handling [greater than 5 gallons] 
 
Refillable container. Refill this container with pesticide only. Do not reuse this 
container for any other purpose. Cleaning the container before final disposal is the 
responsibility of the person disposing of the container. Cleaning before refilling is the 
responsibility of the person refilling. To clean container before final disposal, empty 
the remaining contents from this container into application equipment or mix tank. Fill 
the container about 10 percent full with water. Agitate vigorously or recirculate water 
with the pump for 2 minutes. Pour or pump rinsate into application equipment or 
rinsate collection system. Repeat this rinsing procedure two more times. Then offer 
for recycling if available or puncture and dispose of in a sanitary landfill, or by 
incineration, or by other procedures approved by state and local authorities.

Prefix Herbicide 
Page 34 
 
Container Handling [greater than 5 gallons] 
 
Non-refillable container. Do not reuse or refill this container. Triple rinse container 
(or equivalent) promptly after emptying. Triple rinse as follows: Empty the remaining 
contents into application equipment or a mix tank. Fill the container ¼ full with water. 
Replace and tighten closures. Tip container on its side and roll it back and forth, 
ensuring at least one complete revolution, for 30 seconds. Stand the container on its 
end and tip it back and forth several times. Turn the container over onto its other end 
and tip it back and forth several times. Empty the rinsate into application equipment 
or a mix tank or store rinsate for later use or disposal. Repeat this procedure two 
more times. Then offer for recycling if available or puncture and dispose of in a 
sanitary landfill, or by incineration, or by other procedures approved by state and local 
authorities. 
 
 
For minor spills, leaks, etc., follow all precautions indicated on this label and clean up 
immediately. Take special care to contain spills, leaks, and other accidents to prevent 
further exposure of facilities and equipment. Absorb spilled product with absorbing 
materials and dispose of in an approved waste disposal facility. In the event of a 
major spill, fire, or other emergency, call 1-800-888-8372, day or night. 
 
CONTAINER IS NOT SAFE FOR FOOD, FEED OR DRINKING WATER! 
 
 
CONDITIONS OF SALE AND LIMITATION OF WARRANTY AND LIABILITY 
 
NOTICE: Read the entire Directions for Use and Conditions of Sale and Limitation of 
Warranty and Liability before buying or using this product. If the terms are not 
acceptable, return the product at once, unopened, and the purchase price will be 
refunded. 
 
The Directions for Use of this product must be followed carefully. It is impossible to 
eliminate all risks inherently associated with the use of this product. Crop injury, 
ineffectiveness or other unintended consequences may result because of such factors 
as manner of use or application, weather or crop conditions, presence of other materials 
or other influencing factors in the use of the product, which are beyond the control of 
SYNGENTA CROP PROTECTION, LLC or Seller. To the extent consistent with 
applicable law, Buyer and User agree to hold SYNGENTA and Seller harmless for any 
claims relating to such factors. 
 
SYNGENTA warrants that this product conforms to the chemical description on the label 
and is reasonably fit for the purposes stated in the Directions for Use, subject to the 
inherent risks referred to above, when used in accordance with directions under normal 
use conditions. To the extent consistent with applicable law: (1) this warranty does not 
extend to the use of the product contrary to label instructions or under conditions not 
reasonably foreseeable to or beyond the control of Seller or SYNGENTA, and (2) Buyer 
and User assume the risk of any such use. To the extent consistent with applicable law,

Prefix Herbicide 
Page 35 
 
SYNGENTA MAKES NO WARRANTIES OF MERCHANTABILITY OR OF FITNESS 
FOR A PARTICULAR PURPOSE NOR ANY OTHER EXPRESS OR IMPLIED 
WARRANTY EXCEPT AS WARRANTED BY THIS LABEL. 
 
To the extent consistent with applicable law, in no event shall SYNGENTA be liable for 
any incidental, consequential or special damages resulting from the use or handling of 
this product. TO THE EXTENT CONSISTENT WITH APPLICABLE LAW, THE 
EXCLUSIVE REMEDY OF THE USER OR BUYER, AND THE EXCLUSIVE LIABILITY 
OF SYNGENTA AND SELLER FOR ANY AND ALL CLAIMS, LOSSES, INJURIES 
OR DAMAGES (INCLUDING CLAIMS BASED ON BREACH OF WARRANTY, 
CONTRACT, NEGLIGENCE, TORT, STRICT LIABILITY OR OTHERWISE) 
RESULTING FROM THE USE OR HANDLING OF THIS PRODUCT, SHALL BE THE 
RETURN OF THE PURCHASE PRICE OF THE PRODUCT OR, AT THE ELECTION 
OF SYNGENTA OR SELLER, THE REPLACEMENT OF THE PRODUCT. 
 
SYNGENTA and Seller offer this product, and Buyer and User accept it, subject to the 
foregoing Conditions of Sale and Limitation of Warranty and Liability, which may not be 
modified except by written agreement signed by a duly authorized representative of 
SYNGENTA. 
 
 
Fusilade DX®, Fusion®, Gramoxone® , Karate® Insecticide with Zeon Technology, 
Prefix®, the ALLIANCE FRAME the SYNGENTA Logo are Trademarks of a Syngenta 
Group Company 
 
Aim® trademark of FMC Corporation 
 
Arrow® trademark of Agriliance, LLC 
 
Assure II® trademark of Nissan Chemical Industries, Ltd. 
 
Basagran®, Extreme®, Poast®, Poast Plus®, Pursuit®, Raptor®, and Scepter® 
trademarks of BASF Ag Products 
 
Classic®, Harmony® GT, Synchrony®, Synchrony® XP, and Viton® trademarks of 
E. I. duPont de Nemours and Co. 
 
Clorox® trademark of The Clorox Company. 
 
Cobra®, Resource®, and Select® trademarks of Valent USA Corporation 
 
Compex® trademark of KALO, Inc. 
 
FirstRate® and Glyphomax® trademarks of Dow AgroSciences 
 
Liberty® and LibertyLink® trademarks of Bayer CropScience

Prefix Herbicide 
Page 36 
 
 
Roundup® trademark of Monsanto Company 
 
Ultra Blazer® trademark of United Phosphorus, Inc. 
 
Unite® trademark of United Agri Products 
 
 
”20XX Syngenta 
 
 
For non-emergency (e.g., current product information), call 
Syngenta Crop Protection at 1-800-334-9481. 
 
 
Manufactured for: 
Syngenta Crop Protection, LLC 
P. O. Box 18300 
Greensboro, North Carolina 27419-8300 
 
 
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000100-01268.20241029.Prefix Herbicide.AMEND-1024-HI.pdf