• . Dregon Kate Brown, Governor 

Department of Agriculture 

635 Capitol St NE 

Salem, OR 97301-2532 

11 March 2016 

Tawanda Maignan, Team Leader 

Risk Integration, Minor Use, and Emergency Response Branch 

U.S. EPA Office of Pesticide Programs (7SOSP) 

Document Processing Desk (EMEX) 

Room S4900, One Potomac Yard 

2777 S. Crystal Drive 

Arlington, VA 22202 

-'-~ 

--~-

RE: Section 18 emergency use of pyridate (ToughTM 5EC Herbicide) for postemergence 

weed control in peppermint and spearmint grown in Oregon during 2016, and possible 

use of this request as a template for similar exemptions in other states. 

The Oregon Department of Agriculture (ODA) hereby requests an emergency exemption under 

Section 18 of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), to allow the use of 

pyridate (ToughTM SEC Herbicide, not EPA registered) for postemergence control of certain 

broadleaf weeds in peppermint and spearmint grown in Oregon during 2016. This is our third 

request for this emergency use, but our first such request since the year 2000. 

Background: History of U.S. registration of pyridate and use on mint 

• FIFRA Section 3 registration: Pyridate, formulated as Tough SEC, was first approved for U.S. 

registration by EPA in 1997 (EPA Reg. No. SS947-168, Sandoz Agro), for use on corn and 

peanuts. The registration was transferred to the successor companies Novartis and then 

Syngenta Crop Protection under EPA Reg. No. 100-880. 

• FIFRA Section 18 exemptions in 1999 and 2000: EPA granted emergency exemptions to 

Oregon and other states for use of pyridate in mint, to control weeds that had become 

resistant to registered alternative herbicides. (Tough SEC, Novartis Crop Protection, EPA Reg. 

No. 100-880, EPA File Symbols 99-0R-27 and 00-0R-1 0, and other states.) 

• Residue tolerances established for mint: In May 2000, EPA established residue tolerances of 

0.20 ppm pyridate in/on peppermint tops and spearmint tops in 40 CFR 180.462. 

• FIFRA Section 24(c) registrations: Special Local Need registrations were approved for mint in 

Oregon and other states in 2001 (EPA Reg. No. 100-880, EPA SLN No. OR-01 OOOS, and in 

CA, ID, IN, Ml, WA, WI.) 

• U.S. pyridate registrations cancelled: All U.S. pyridate registrations were voluntarily cancelled 

by Syngenta Crop Protection in 2004, but EPA extended all state mint SLNs through 2007. 

2016 Section 18 Request 

• Emergency situation: To date, efficacious alternatives have not been registered for postemergence control of certain herbicide-resistant broadleaf weeds in mint that formerly were 

controlled by pyridate. In fields infested with these weeds, especially redroot pigweed and 

kochia in Oregon, growers continue to suffer significant economic loss due to both lower yields 

of mint oil and lower prices received for oil tainted by off-flavors imparted by these weeds. 
§ 18/Pyridate.mint. Oregon/2016 

11 March 2016 

page 2 

• New U.S. pyridate registration (in progress): ODA has been informed that Syngenta recently 

transferred the U.S. marketing rights for pyridate to the Belchim Crop Protection company of 

Belgium, and that Belchim has had initial meetings with EPA to discuss reestablishing U.S. 

registration of pyridate on certain crops, including mint. 

• Although pyridate residue tolerances for mint remain in effect in 40 CFR 180.462, EPA has 

advised ODA that pursuing a Section 24(c) SLN registration is not a viable option because 

there are currently no Section 3 registrations for pyridate, but that a Section 18 might be 

considered a reasonable option (email communication from Marion Johnson). The Mint 

Industry Research Council (MIRC) has obtained support of Belchim for Section 18 emergency 

exemption requests for Oregon and other states in 2016. 

• Other states may cite this Oregon request: On behalf of mint growers inCA, ID, IN, Ml, WA, 

WI , the MIRC has collaborated with ODA to offer this Oregon request as a template that can 

be cited by other State Lead Agencies for similar Section 18 requests in those states. Each 

other state that wishes to pursue a Section 18 request may cite any information in this Oregon 

request, while providing its own state-specific information on affected acreage and proposed 

use details/directions, enforcement programs, environmental and endangered/threatened 

species concerns, and significant economic loss (SEL) analysis. It is ODA's understanding that 

this multiple-state exemption approach is allowed under EPA's Section 18 guidelines. 

• Information required in 40 CFR 166.20 for Oregon is provided in the following pages. 

Please contact me if there are questions about this request. 

David L. Priebe 

Pesticides Program 

Phone: (503)986-4656 

FAX: (503)986-4735 

Email: dpriebe@oda.state.or.us 

cc: Steve Salisbury, Mint Industry Research Council 

Bryan Ostlund, Oregon Mint Commission 

Carol Mallory-Smith, Oregon State University 

Liesbeth Bosman, Belchim Crop Protection 

Eric Maurer, Engage Agro USA 

Ted Buerger, U.S. Fish and Wildlife Service 

Ben Miller, Idaho State Department of Agriculture 

Erik Johansen/Steve Foss, Washington State Department of Agriculture 

Jill Townzen/Margaret Reiff, California Department of Pesticide Regulation 

Ed White, Office of the Indiana State Chemist 

Brian Verhougstraete, Michigan Department of Agriculture & Rural Development 

Otto Oemig, Wisconsin Department of Agriculture, Trade and Consumer Protection 

Rose Kachadoorian, ODA Registration Team Leader 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

Request for FIFRA Section 18 Emergency Exemption 

for Use of Pyridate (Tough TM 5 EC Herbicide) 

for Postemergence Broad leaf Weed Control in Mint Grown in Oregon 

A. Summary of General Information Required in 40 CFR 166.20(a). 

1. Type of Exemption: Specific. 

2. Contact Persons: 

Steve Salisbury (Technical) 

Mint Industry Research Council 

PO Box 4059 

Salem, OR 97302-1059 

Phone: 503-551-3747 

Email: steve@pacificagresources.com 

Dr. Carol Mallory-Smith (Scientific) 

Department of Crop and Soil Science 

Oregon State University 

Corvallis, OR 97331-3002 

Phone:503-737-5883 

Email: Caroi.Mallorv-Smith@oregonstate.edu 

Bryan Ostlund (Economics) 

Oregon Mint Commission 

P.O. Box 3366 

Salem, OR 97302 

Phone: 503-363-3346 

Email: bryan@ostlund.com 

Liesbeth Bosman (Manufacturer/Registrant) 

Belchim Crop Protection, Inc. 

Technologielaan 7 

1840 Londerzeel 

Belgium 

Phone: +32 (0) 473 86 52 33 

Email: Liesbeth.Bosman@Belchim.com 

Eric Maurer (U.S. Distributor) 

Engage Agro USA, LLC 

118 E. Carleton Street, Suite B 

Prescott, AZ 86303 

Phone: 410-703-3756 

Email: ericmaurer@engE.geagro.com 

3. Description of the Pesticide. 

page 3 

a. Active Ingredient: Pyridate; 0-(6-chloro-3-phenyl-4-pyridazinyi)-S-octyl-carbonothioate; 

CAS No. 55512-33-9. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

b. Trade Name: ToughTM 5 EC Herbicide, not currently r~istered in U.S. 

page 4 

c. Formulation: Emulsifiable concentrate containing 55.8% active ingredient, equivalent to 

5 lb. pyridate per gallon. 

d. Registrant/Manufacturer: Belchim Crop Protection; Londerzeel, Belgium. 

e. U.S. Distributor: Engage Agro USA, LLC; Prescott, Arizona. 

The proposed U.S. marketing/container label and Safety Data Sheet (SDS) for the product are 

enclosed as Attachments #1 and #2, respectively. 

4. Description of the Proposed Use. 

a. Sites to be Treated: Peppermint and spearmint grown in the following regions/counties in · 

Oregon. 

Central and Eastern Oregon: Crook, Deschutes, Harney, Lake, Malheur, Morrow, 

Umatilla, and Union counties 

Southern Oregon: Klamath County 

Western Oregon (Willamette Valley): Benton, Clackamas, Lane, Linn, Marion, Polk, and 

Yamhill counties 

b. Method of Application: ToughTM may be applied to mint using ground equipment only. For 

best control of broad leaf weeds, applications should be targeted to actively growing weeds 

by the 4-leaf stage (approximately 3 inches in height or less). 

c. Rate of Application: Applications may be made at the rate of 24 fl. oz. of product (0.94 lb. 

a.i. pyridate) per acre, in 20-40 gallons of water per acre. 

d. Maximum Number of Applications: A maximum of two applications may be made, totaling 

no more than 48 fl. oz. Tough TM (1 .88 lb. a.i. pyridate) per acre per season. A minimum 

14-day interval must be observed between applications. 

e. Total Acreage to be Treated: There are approximately 18,000 acres of mint grown in 

Oregon. The emergency weed situation affects about half (50%) of this total acreage. 

Thus, approximately 9,000 acres could potentially be treated with Tough TM 5 EC Herbicide 

under this exemption, if granted. 

f. Total Amount of Pesticide to be Used: Based on the maximum seasonal application rate of 

48 fl. oz. product per acre, a maximum of 3,375 gallons of ToughTM 5 EC Herbicide 

(16,875 lb. a.i. pyridate) may be applied to a maximum of 9,000 acres in Oregon. 

g. Use Season: The requested use period is from April1 through December 31, 2016. A fall 

application after harvest may be necessary if conditions promoting weed growth occur. 

h. Harvest Dates: The majority of peppermint acreage is harvested once, in August. 

However, some peppermint growers are double cutting their crop. Double-cut mint is 

harvested twice during the growing year, once in mid- to late June and again in late August 

or early September. Spearmint is harvested twice during the growing season, once in the 

middle of June and again in the middle of August. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

i. Additional Use Information, Requirements, and Restrictions: 

page 5 

All precautionary/hazard and worker protection information on the main product container 

label for Tough TM 5 EC Herbicide (Attachment #1) must be followed. 

Do not enter or allow worker entry into treated areas during the restricted-entry interval 

(REI) of 24 hours. 

Do not apply more than 48 fl. oz. of ToughTM (1.88 lb. a.i. pyridate) per acre per season, as 

a result of no more than two (2) applications. A minimum 14-day interval must be observed 

between applications. 

Do not apply ToughTM to mint within 49 days before harvest. 

Do not apply ToughTM to mint by air or through any type of irrigation equipment. 

Treated fields or forage from treated fields may not be used for livestock feed or grazing. 

To protect endangered plant species, one of the following options must be used: 

(1) Apply only when there is a sustained wind away from wetland/transitional zone 

native plant communities; 

(2) Leave a 25-foot buffer between treatment area and wetland/transitional zone 

native plant communities; or 

(3) Use low pressure nozzles according to manufacturer's specifications that produce 

only coarse or very coarse droplets. 

To protect endangered freshwater invertebrate species, do not apply ToughTM within 100 

yards of any freshwater spring. 

Any adverse effects that may result from the use of Tough TM under this emergency 

exemption must be immediately reported to the Oregon Department of Agriculture. 

Any unused, unregistered product must either be returned to the manufacturer or 

distributor (unopened containers), or be disposed of in accordance with the Resource 

Conservation and Recovery Act (RCRA) regulations following the expiration of the 

emergency exemption. 

The product container label for Tough TM 5 EC Herbicide and the Oregon Section 18 use 

directions for mint must be in possession of the user at the time of pesticide applications. 

A draft Section 18 use directions document for emergency exemption use of ToughTM 5 

EC Herbicide on mint in Oregon is enclosed as Attachment #3. 

5. Alternative Methods of Control. 

a. Registered Postemergence Herbicide Alternatives: 

1. Bentazon (Basagran)- Provides inconsistent (partial) postemergence control of kochia. 

Does not control pigweed. Weeds emerging after application are not controlled. 

2. Bromoxynil (Maestro)- Phytotoxic to actively growing mint. Cannot be applied above 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

page 6 

70° F to actively growing mint. Only gives partial control of kochia and pigweed 

seedlings. Kochia and pigweed seeds germinate (multiple flushes) throughout the 

growing season. 

3. Clethodim (Select Max)- Grass weed control only. 

4. Clopyralid (Stinger) - For spot treatment, postemergence control of broadleaf weeds 

(Canada thistle, dandelion) only. Destroys mint that comes in contact with herbicide. 

Does not control kochia or pigweed. 

5. MCPB {Thistrol)- Can only be applied early postemergence to weeds and to dormant 

or small/newly emerged mint. It is limited to partial control of Canada thistle and field 

bindweed. Does cause crop injury and loss of oil yield. 

6. Quizalifop (Assure II) - Grass weed control only. 

7. Sethoxydim (Poast Plus) - Grass weed control only. 

8. Terbacil (Sinbar)- Does not control kochia. Pigweed has developed resistant biotypes 

due to years of continuous use. It is not effective on weeds that have grown beyond the 

seedling stage. Cannot be used when rotating from mint into other crops the following 

year, due to soil persistence and crop rotational restrictions. Cannot be used on sandy 

soils, loamy sands, or soils with less than 1% organic matter without crop injury. 

b. Other Weed Control Alternatives: Mechanical weed control methods such as tillage are not 

feasible or practiced in actively growing mint due to the destruction of the crop. Tillage in 

mint at any time also spreads the disease Verticillium wilt, a fungal pathogen in mint that is 

spread by the movement of soil and debris. Tillage also spreads the rhizomes and stolons 

of perennial weeds. Hand rogueing is cost prohibitive and does not provide season-long 

control of weeds, as weed seeds continue to germinate in the soil throughout the growing 

season. In addition, the labor needed for hand weeding is not available in most mint 

growing regions. Crop rotation is practiced when feasible; but mint, being a perennial crop, 

is usually left in production for 3 to 5 years or longer. Research on biological control 

methods is currently being conducted, but to date no effective methods have been 

developed. 

c. Ongoing Research for Chemical Alternatives: The mint industry has placed a high priority 

on finding alternatives to pyridate for postemergence broad leaf weed control. The industry 

has diligently invested several hundred thousands of dollars of research funds for the past 

decade to this effort. Numerous preemergence and postemergence herbicides have been 

tested and evaluated, with little or no success. Preemergence herbicides evaluated 

include pendimethalin, terbacil, saflufenacil, sulfentrazone, flumioxazin, oxyfluorfen, 

pyroxasulfone, and both oxyfluorfen and flumioxazin impregnated on fertilizer have been 

tested. Postemergence herbicides that have been tested include bentazon, terbacil, 

bromoxynil, bicyclopyrone, mesotrione, tembotrione, topramezone, fluroxypyr, MCPB, and 

carfentrazone. These herbicides are either too injurious to the mint or do not adequately 

control the pigweed. A letter from Dr. Rick Boydston, USDA-ARS, summarizing mint 

herbicide research since 2006 is enclosed as Attachment #4. 

In summary, despite extensive efforts, the mint industry has not been able to successfully 

find an adequate replacement for pyridate (since cancellation of its U.S. registrations in 

2007) to provide postemergence weed control that does not cause significant injury to the 
§ 18/Pyridate.mint.Oregon/20 16 

11 March 2016 

page 7 

mint crop. Therefore, weed control remains an urgent situation challenging the ability to 

produce high quality mint oil. 

In addition to the urgency of the situation, it is important to note that postemergence 

broadleaf weed control has recently developed into a non-routine situation due to the 

increased demand for double-cut mint production acreage. Many acres have been forced 

to double-cut production to meet recent global regulatory and market demands. Further 

description of this non-routine situation is discussed below, in Section B, Part 2 

(Description of the Emergency Condition) of this request. 

6. Efficacy of the Proposed Use. 

Results of efficacy and comparative field trials involving pyridate (ToughTM) are enclosed as 

Attachment #5. It is noteworthy that these efficacy and crop safety trials were all conducted 

back in the 1990s, during the period in which the mint industry and the former U.S. registrant of 

pyridate (Novartis/Syngenta Crop Protection) were developing data in support of residue 

tolerances (established in 2000) and registration on mint (SLNs approved in 2001 ). There are 

no more recent data available, which is not unexpected, because there had been no 

expectation that pyridate might become available in the U.S. once again. 

Tough TM selectively controls annual weeds in mint without causing significant crop injury. Risks 

to rotational crops are minimized due to the short half-life and low soil persistence, leading to 

no residual impact to subsequent crops. Tough TM is the only known broad leaf herbicide that 

can provide postemergence control of weeds without impacting crop yield (see Attachment #6). 

7. Residue Information. 

Residue trials for pyridate/mint were conducted by the IR-4 Program in 1994. Applications 

made in accordance with the requested provisions for this exemption are not expected to result 

in residues of pyridate and its metabolites in excess of 0.2 ppm in peppermint tops and 

spearmint tops. There are no feed items associated with mint; therefore, secondary residues 

are not expected to occur in meat, milk, poultry, or eggs as a result of the proposed use. 

Mint residue tolerances were established by EPA in 40 CFR 180.462 at 0.2 ppm in May 2000. 

Although U.S. registrations of pyridate on mint were canceled in 2007, the tolerances remain in 

effect to this day. 

8. Risk Information. 

a. Worker/Handler Occupational Risks: The proposed ToughTM 5 EC Herbicide product label 

(Attachment #1) addresses the risks to worker/applicator by outlining handler precautions 

and required personal protective equipment. These worker protection statements mirror 

those on the label of the product when formerly registered in the U.S. under EPA Reg. No. 

100-880. 

b. Human Health Dietary Risks: EPA completed a comprehensive risk assessment in 

conjunction with the establishment of the mint residue tolerances in May 2000. Data and 

other information concerning pyridate toxicology, endocrine effects, mode of action, 

aggregate exposure (including exposures through drinking water), and safety for the U.S. 

population and infants and chi ldren, were evaluated, and the safety determination was 

made, in order to set those tolerances. Information relevant to this risk assessment was 
§ 18/Pyridate .mint. Oregon/20 16 

11 March 2016 

page 8 

presented in the final rule published in: Federal Register, 03 May 2000 (Volume 65, 

Number 86), pages 25647-25652. A copy is enclosed as Attachment #7. 

ToughTM herbicide poses little potential risks to humans, domestic animals, wildlife, and 

the environment. The acute oral LD50 for male rats is > 5,000 mg/kg. The active ingredient 

has a low dermal irritation potential and a low inhalation hazard. Acute dermal LDso for 

rabbits is > 2,000 mg/kg. Inhalation LCso is > 4.37 mg/L air. Primary dermal irritation study 

indicated it is mildly irritating to rabbit skin. (See EPA Health Effects Division Risk 

Assessment, January 2000, enclosed as Attachment #8.) 

EPA concluded that residues of pyridate in drinking water do not contribute significantly to 

the aggregate acute human health risk. The acute human health risks resulting from 

exposure to pyridate in food and water are below EPA's level of concern for all population 

subgroups. As for chronic risk, the EPA also concluded that no harm will result from 

aggregate chronic exposure. 

The potential for exposure to residues of pyridate in drinking water is negligible due to its 

low water solubility (1.5 mg/L at 20°C), strong soil adsorption (Kd = 0.3-3.5) and short 

half-life (7-21 days). Pyridate is essentially immobile in all soil types and any risks to 

surface or groundwater contamination will be negligible. 

The EPA Health Effects Division determined that pyridate does not possess the 

environmental fate parameters associated with a compound that could leach to 

groundwater. However, the parameters of its degradate indicate that under unusual 

conditions such as flooding, where anaerobic conditions persist in topsoil for up to 60 

days, the degradate could possibly leach to groundwater or run off to surface water. 

Pyridate is not listed in the EPA Pesticides in Ground Water Database, nor is there an EPA 

Maximum Containment Level or health advisory. 

It was also determined that pyridate is not carcinogenic in either rat or mouse, and 

therefore is not expected to pose a cancer risk to humans. 

c. Residential Uses: Pyridate is not registered for use in ornamentals or in residential areas. 

d. Common Mode of Action: Pyridate is a Group 6 herbicide, HRAC Group C3 (Herbicide 

Resistance Action Committee, www.hracglobal.com). It belongs to the phenyl-pyridazine 

family of herbicides. Its site of action is inhibition photosynthesis by blocking electron 

transport in photosystem II (reactions taking place in the chloroplast thylakoid 

membranes). 

e. Endangered or Threatened species: Endangered or threatened species listed by the 

USFWS within the mint production counties of Marion, Polk, Yamhill, Clackamas, Linn, 

Benton, Lane, Malheur, Crook, Union, Umatilla, Morrow, Harney, Lake, Deschutes, and 

Klamath are provided in Attachment #9. 

The use of ToughTM herbicide in accordance with the label in mint fields should not pose a 

risk to any threatened or endangered species. 

f. Beneficial Organisms: ToughTM herbicide is not toxic to bees and other beneficial insects 

(e.g., lady beetles, predatory mites). See the EPA Environmental Fate and Effects Division 

report, December 1989, enclosed as Attachment #1 0. 
§ 18/Pyridate.mint.Oregon/20 16 

11 March 2016 

g. Fish and Aquatic Organisms: Pyridate is considered toxic to estuarine organisms. 

page 9 

However, due to its strong soil adsorption and short half-life, if applied according to the 

label it should not pose a risk to estuarine organisms (see Attachment #1 0). The proposed 

label states that this material should not be applied within 100 yards of any freshwater 

spring, directly to water, to areas where surface water is present, or to intertidal areas 

below the mean high water mark. 

9. Coordination with Other Agencies. 

The Oregon Fish and Wildlife Office of the U.S. Fish and Wildlife Service will receive a copy of 

this request. Any comments received will be forwarded to EPA. 

10. Notification of Registrant. 

Belchim Crop Protection has been notified and their letter of support is enclosed as Attachment 

#11. Engage Agro USA, LLC, which will serve as the U.S. distributor of Tough TM S EC 

Herbicide, has also provided a letter of support, enclosed as Attachment #12. 

11. Enforcement Program. 

The Oregon Department of Agriculture (ODA) has adequate authorities for enforcing provisions 

of Section 18 emergency exemptions. ODA will require the registrant (manufacturer, if 

unregistered) of Tough TM S EC Herbicide, Belchim Crop Protection, to prepare and make 

available to end users Section 18 Use Directions that comply with ODA and EPA requirements 

for the emergency use, if approved. Applicators will be required to keep adequate records of 

application use and acreage. The Mint Industry Research Council (MIRC), in cooperation with 

Belchim Crop Protection and Engage Agro USA, will be required to provide the ODA a report 

summarizing results of the emergency use after the end of the use period. 

12. Repeat Uses. 

EPA granted Section 18 emergency exemptions for use of pyridate (Tough SEC, Novartis Crop 

Protection, EPA Reg. No. 1 00-880) on mint in Oregon in 1999 and 2000, EPA File Symbols 

99-0R-27 and 00-0R-10. 

After mint residue tolerances were established in May 2000, ODA registered Tough SEC on 

mint under FIFRA Section 24(c), EPA SLN No. OR-01000S. EPA and Syngenta Crop 

Protection voluntarily canceled the U.S. registrations of pyridate in 2004, but allowed the mint 

SLN to remain registered until the end of 2007. 

This is the third time that ODA has requested use of pyridate on mint under FIFRA Section 18. 

13. Progress Toward Registration. 

Pyridate/mint residue tolerances of 0.20 ppm in peppermint tops and spearmint tops were 

established by EPA in May 2000 (Attachment #7). Use of Tough SEC on mint was registered in 

several states under FIFRA Section 24(c), but all U.S. registrations of pyridate were voluntarily 

cancelled by Syngenta Crop Protection and EPA at the end of 2007. 

Recently, Belchim Crop Protection of Belgium acquired the U.S. marketing rights for pyridate 

from Syngenta. It is understood that Belchim is working with the EPA to re-register pyridate on 

mint in the U.S. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

B. Summary of the Economic Loss Information Required in 40 CFR 166.20(b). 

1. Pests to be Controlled. 

The pests causing an emergency are broad leaf weeds that have become resistant to 

registered postemergence herbicides, in particular: 

Redroot pigweed, Armaranthus retroflexus 

Kochia, Kochia scoparia 

2. Discussion of the Emergency Condition. 

page 10 

This request is due to the emergency condition existing in mint from pigweed, kochia, and other 

broadleaf weed communities that cannot be effectively controlled postemergence in active 

growing mint crops. All crops including mint suffer yield losses from populations of weeds, but 

unlike other crops, the quality of mint oil also is affected by weeds. A quality marketable mint 

crop is dependent upon weed-free fields . 

Redroot pigweed present in mint at 1.6 weeds/yd2 renders mint oil unmarketable, due to 

off-flavors imparted during the distillation process (see Attachment #13). Research at Oregon 

State University (OSU) also demonstrated that a redroot pigweed infestation of 10 plants/ft2 

caused a peppermint oil yield reduction 34.4 lb/acre, a 46% reduction (Attachment #13). 

Furthermore, both redroot and prostrate (A. blitoides) pigweeds have developed biotypes that 

are resistant to terbacil (Sinbar), the most commonly used postemergence broadleaf herbicide 

in mint (see Attachments #14 and #15). 

Kochia, a summer annual, can grow to heights of six feet and several feet in diameter, 

hindering harvest operations and competing for nutrients and light. An infestation of 2.3 kochia 

plants/fe can reduce mint oil yields by over 30% in addition to reducing oil quality (Attachment 

#13). 

Mechanical tillage is not a postemergence weed control option in mint because tillage will 

destroy growing mint, eliminate irrigation rills in surface irrigated fields, and will spread 

devastating diseases in mint such as Verticillium wilt (Verticillium dahliae). Terbacil (Sinbar), 

the commonly used herbicide registered for weed control in mint, is weak on pigweed species 

and has become even less effective in controlling pigweeds due to the development of resistant 

biotypes (Attachments #14 and #15). Additionally, terbacil cannot be used when weeds are 

beyond the seedling stage and when rotating from mint to other crops due to residual 

carryover. The only alternative method of controlling these weeds is hand-rogueing, but the 

unavailability of labor and excessive cost where labor is available, eliminates rogueing as a 

viable weed control method. Again, there are presently no effective postemergence means of 

controlling these weeds in mint. 

The recent increase in global demand for the production of double-cut mint oil has created a 

non-routine situation that poses additional stress on the need for adequate postemergence 

broad leaf weed control. Preemergence herbicides applied in February/early March to dormant 

mint dissipate to low levels that no longer control weeds after 4-6 weeks. The mint crop canopy 

suppresses any new weed emergence or establishment after this period. Once the mint canopy 

is removed with a mid- to late June harvest (first cutting), new weed flushes follow. These new 

flushes include both summer annual grasses and later germinating broadleaf weeds such as 

pigweeds. The grass weeds are easily controlled with registered grass active herbicides. 

However, there are no effective postemergence herbicides that are labeled in mint for pigweed 

control during the second half of the growing season following the first harvest of mint. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

page 11 

The increased demand for double-cut mint is a result of both global regulatory challenges and 

the increasing desire for the oil quality that is produced in double-cut production. The global 

regulatory issues involve the concern of menthofuran and pulegone contents in the mint oil, 

and the limits of these compounds that are allowable in oil to deem it acceptable in markets. 

The reduction of these compounds and the increase of other desirable oil quality traits can be 

achieved through double-cut production. The market has shifted to a higher demand for 

double-cut mint, but the acreage to meet the demand is not adequate due to management 

challenges associated with double-cut production. Postemergence broad leaf weed control is 

the primary management challenge facing double-cut production. Producers do not have viable 

broadleaf weed control options to address this challenge. 

The mint industry has been diligently investing research funds to discover effective 

postemergence broad leaf weed herbicides that are safe to the crop. Pyridate has proven to be 

effective on broad leaf weeds, as well as possessing acceptable postemergence crop safety 

needed for mint production. Populations of problem weeds have reached economically 

devastating levels and are impacting the producers' ability to compete in the market. 

Additionally, the recent increased demand for double-cut mint has forced production into and 

created a non-routine situation for mint producers who have no effective and viable 

postemergence broad leaf weed control options. The use of pyridate/ Tough TM 5 EC Herbicide 

for postemergence weed control in mint is critical to maintaining U.S. mint oil quality and 

market share in today's global economy. 

3. Discussion of Economic Loss. 

Kochia/redroot pigweed and other broad leaf weed communities have become serious weed 

pests of mint growers in Oregon. The lack of any postemergence broad leaf weed control option 

(no effective registered herbicide, and presence of herbicide-resistant pigweed) has created an 

emergency situation for Oregon mint growers. Furthermore, the recent increased demand for 

double-cut mint has created a non-routine situation in weed control for mint producers. 

Economic thresholds for these problem weeds are very low. Weeds resistant to herbicides 

which mature and form seeds, soon establish large populations of the resistant biotype, if not 

controlled. 

Studies performed by OSU weed scientists show yield losses ranging from 22% to 47% from 

the target weeds individually (Attachment #13). Kochia and redroot pigweed are often found in 

complexes of other weeds, which further reduces the yield and quality of mi~t oil. 

Significant Economic Loss (SEL) -Tier 2 Analysis 

The first table below shows the five-year economic history of mint oil production in Oregon. As 

footnoted below the table, yield and price data were obtained from mint growers and oil buyers. 

These data represent oil yield across all mint acres in Oregon, i.e., from both fields infested 

with the problem weeds and uninfested fields, collectively. In the second table, a Tier 2 SEL 

analysis is used to illustrate the impact of reductions in both yield and quality of mint oil leading 

to loss of revenue due to the devaluation of tainted oil resulting from weed contaminants. 

Tier 2 yield calculations are based on the five-year average (2011 -2015) of 84 lb/acre. The 

baseline vs. emergency comparison reflects a 35% yield reduction (based on OSU trial data) 

on the portion of the acres (50%) faced with the impact of postemergence weed control 

challenges. As previously stated in this request, the estimated acreage of Oregon mint is 

18,000 acres and approximately 9,000 acres (50%) have the emergency weed infestations. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

F" IVe· y ear H1story " o 

Year 

Average 

Yield1 

Average 

Price1 

(lb oil/acre) ($/lb oil) 

2011 81 $21 

2012 82 $21 

2013 85 $21 

2014 83 $21 

2015 88 $21 

Average 84 $21 

fO 

page 12 

reg on p ro d uc f 1on o f M" m t 0"1 I 

Gross Cost of Net 

Revenue Production2 Revenue3 

($/acre) ($/acre) ($/acre) 

$1,705 $2,038 ($333) 

$1,725 $2,038 ($313) 

$1,788 $2,038 ($250) 

$1,750 $2,038 ($288) 

$1,849 $2,038 ($189) 

$1,763 $2,038 ($275) 

1 Yield and price data were obtained from mint industry oil growers and buyers. 2 Cost of production is based on 2013 University of Idaho Enterprise Budget (Attachment #16). 

Oregon was not used because the most recent university budget was published in 1995. 

3 A loss does not necessarily mean a negative cash flow, but rather that the grower will not earn a 

return on capital and management contributions (hourly wage, labor, etc.) equal to what could be 

earned in an alternative investment of the land producing the mint crop. 

As for marketable oil quality, it is estimated that control of the problem weeds will reduce the 

amount of tainted oil produced (i.e., increase production of untainted oil) by 20% overall. The 

price devaluation of tainted oil ranges from a small percentage deduction to complete 

rejection/loss. Based on industry knowledge, an average devaluation of 35% was used for this 

analysis. 

The emergency situation results in 20% more tainted oil that has 35% less value realized by the 

growers. In all, this is a loss greater than $10 million to the mint producers in Oregon. 

Tier 2 Oregon Economic Analysis of Yield and Quality Loss 

Baseline Emergency Change %Change 

Total Oil Yield** 1,919,077 1,512,000 -407,077 -21% (lb./18,000 acres) 

Untainted Oil 90% 70% (%of yield) 

(total lb.) 1 ,727,169 1,058,400 -668,769 -39% 

Tainted Oil 10% 30% (%of yield) 

(total lb.) 191,908 453,600 261,692 +136% 

Price, Untainted ($/lb) $21 .00 $21 .00 

Price, Tainted ($/lb} $13.65 $13.65 -$7.35 -35% 

Gross Revenue $38,890,093 $28,418,040 -$10,472,053 -27% ($/acre) 

** Total mint oil yield in current (emergency) situation across all 18,000 acres at average yield 

of 84 lb/ac = [18,000 x 84 lb/ac] = 1 ,512,000 lb. 

Baseline yield expected to be achieved without the emergency situation, calculated across 

all 18,000 acres = [9,000 ac x 84 lb/ac] + [9,000 ac x (84 lb/ac/0.65)] = 1 ,919,077 lb. 
§ 18/Pyridate.mint.Oregon/2016 

11 March 2016 

C. Supporting Documentation 

Attachment# Cited in Request 

1. Tough TM 5 EC Herbicide container label (proposed). 

2. Tough TM 5 EC Herbicide Safety Data Sheet (SDS). 

page 13 

3. ToughrM 5 EC Herbicide proposed Section 18 Use Directions for mint in Oregon in 2016. 

4. Letter summarizing weed research efforts searching for alternatives to pyridate. Dr. Rick 

Boydston. USDA-ARS. Prosser, WA. March 1, 2016. 

5. Tolerance of Peppermint to Pyridate. Oregon State University Efficacy Data. Hyslop Farm, 

Corvallis, OR. 1993. 

6. Pyridate Properties and Characteristics. Heap, I. pp. 89-91 . 

7. Final rule to establish pyridate residue tolerances for mint. Federal Register, Vol. 65, No. 

86. Wednesday, May 3, 2000. pp. 25647-25652. 

8. EPA Health Effects Division Risk Assessment. Pyridate (i.e. Tough®) in/or on Brassica 

Head and Stem Subgroup, Collards and Mint. January 24, 2000. 

9. Endangered/Threatened Species Found in Oregon Mint Producing Counties. February 

2016. http://ecos.fws.gov/tess public/ 

10. EPA Environmental Fate and Effects Division- Pyridate Report. December 12, 1989. 

11. Belchim Crop Protection N.V./S.A. Letter of Support. January 13, 2016. 

12. Engage Agro USA, LLC. Letter of Support. February 4, 2016. 

13. The Effect of Weeds on Mint Oil Yield and Quality. Heap, I. Department of Crop and Soil 

Science. Oregon State University. 

14. Herbicide Resistant Weeds in Mint. Heap, I. WeedSmart, Corvallis, OR. 

15. Terbacil and Bromacil Cross-Resistance in Powell Amaranth (Amaranths powellit). 

Boydston, Rand AI-Khatib, K. Weed Science. Volume 40:513-516. 1992. 

16. Costs & Returns Estimates for Peppermint Establishment & Production Center Pivot, No 

Fumigation. Painter, K, et.al. University of Idaho. 2013