March 31 , 2016 

Petition for Section 18 Emergency Exemption for Tough® 

Herbicide (pyridate) for use in mint grown in Indiana 

A. Summary of General Information 

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 

Or. Steve Weller (Scientific) 

Department of Horticulture & Landscape Architecture 

Purdue University 

625 Agriculture Mall Drive 

West Lafayette, IN 47907-2010 

Phone: 765-494-1333 

Email: weller@purdue.edu 

Jerry Frankhauser (Economics) 

Purdue Agricultural Centers 

Purdue University 

615 West State Street 

West Lafayette, IN 47907-2053 

Phone: 765-494-8368 

Email: frankhaus@purdue.edu 

Liesbeth Bosman (Registrant) 

Belchim Crop Potection, Inc. 

Technologielaan 7 

1840 Londerzeel 

Belgium 

Phone: +32 (0) 473 86 52 33 

Email: Liesbeth.Bosman@Belchim.com 

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2. Contact Persons (continued): 

Edward M. White, Assistant Pesticide Administrator (Regulatory Issues) 

Office of the Indiana State Chemist 

175 S. University Street 

Purdue University 

West Lafayette, lN 47907-2063 

Phone: 765-494-1587 

Email: ewhite@purdue.edu 

3. Description of Pesticide 

Active Ingredient: Pyridate 

Trade Name: Tough Herbicide SEC, not currently registered in U.S. 

Formulation: Emulsifiable concentrate formu lated at 55.8% (5.0 lb. ai. per gal.) and 44.2 

% inert ingredients. 

Registrant/Manufacturer: Belchim Crop Protection a Belgium based company (EPA 

Company No. 91746). The U.S. distributor is Engage Agro USA Corp. Material Safety 

Data Sheet (MSDS) and labels are attached. 

4. Description of Proposed Use 

a. Sites to be Treated 

There are nearly 14,000 acres of mint grown in Indiana. It is estimated that approximately 

II ,200 (80%) of this acreage will need to be treated with Tough. The mint production 

areas are located in Indiana counties of Jasper, Kosciusko, LaGrange, La Porte, Newton, 

Porter, Pulaski, Stark, and St. Joseph. The soils of these mint growing counties are 

generally productive, deep, and ferti le in agricultural areas. 

b. Method of Application 

The herbicide will be applied by ground-driven spray equipment by licensed applicators 

according to the EPA approved product label. Tough will not be applied by aerial 

methods or through any type of irrigation system. 

c. Rate of Application 

A maximum of .9375 lb. active ingredient per acre (24 ounces of product per acre) in 2crr•• • 

40 gallons of water per acre will be applied during the growing season. : • •: •: • • • • 

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d. Maximum Number of Applications .. : • •: 

Two applications ofTough per growing season may be made if necessary a :· • • 

minimum of 14 days between applications. Applications may be made bet\: ti<!11 the dat~~ • 

of April I and December 31, 20 16. No applications will be made within 4~ da_ys of • •. 

harvest. : • •' • • 

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e. Total Acreage to be Treated 

It is estimated that approximately 11,200 acres (80% of total Indiana acreage) will need 

to be treated with Tough. 

f. Total pesticide to be used 

An estimated 4,200 gallons (21 ,000 lbs of a.i.) of herbicide are expected to be applied. 

II ,200 acre * 24 tl.oz. * 2 applications = 4,200 gal. of formu lated product. 

4,200 gal * 5 lb a.i./ gal = 21 ,000 lbs of active ingredient. 

g. Use season 

We are requesting application beginning April 1 through December 31, 20 I 6. A fall 

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

No applications will be made within 49 days of harvest. 

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 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. 

i. Other Restrictions. User Precautions. and Requirements 

Federal and supplemental labels address reentry and worker protection, environmental 

hazards and restrictions (see attached label). Treated fields or forage from treated fields 

may not be used for livestock feed or grazing. Tough will not be applied through any type 

of irrigation system or by air. To protect endangered freshwater invertebrate species, 

Tough will not be applied within I 00 yards of any freshwater spring. 

5. Alternative Methods of Control 

a. Registered Post-Emergent Herbicide Alternatives 

1. Bentazon (Basagran) - Provides inconsistent (partial) post-emergence 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 70 degrees F to actively growing mint. Only gives partial cont~q Q{ l<och .:. 

and Pigweed seedlings. Kochia and Pigweed seeds germinate (multirile fl hes) 

throughout the growing season. • • 

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

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4. Clopryalid (Stinger)- For spot treatment, post emergence control ofbroadleafweeds 

(canada thistle, dandelion). Destroys mint which comes in contact with herbicde. 

Does not control Kochia or Pigweed 

5. MCPB (Thistrol) - Can only be applied early post-emergent to weeds and to 

dormant or small/newly emerged mint. lt 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. Sethoxyd im (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 restriction. Cannot be 

used on sandy, loamy sands, or soils with less than I% organic matter without crop 

injury. 

b. Other 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 which is spread by the movement 

of soil and debris. Tillage also spreads the rhizomes and stolons of perennial weeds. Hand 

rogueing is cost proh ibitive and does not provide season long control of weeds as weed 

seeds continue to germinate in the soil throughout 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 left in production for 3 to 5 

years, or longer. Research on biological control methods is currently being conducted, but 

as ofto date no effective methods have been developed. 

c. On-going research for chemical alternatives 

Them int 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 pendamethalin, terbacil, 

saflufenacil, sulfentrazone, flumioxazin, oxyfluorfen, pyroxasulfone and both oxyfluorfen 

•••• and flumioxazin impregnated on fertilizer have been tested. os emergenc~ Vf ~~c ides ~ 

have been tested include bentazon, terbacil, bromoxynil, bicyclopyrone, mesotti<lne, • 

tembotrione, topramezone, fluroxypyr, MCPB, and carfentrazone. These herbicides are •••••• either too injurious to the mint or do not adequately control the pigweed. A r: from Dr. 

Rick Boydston, USDA-ARS, is attached summarizing mint herbicide research•si nce 200 : • • ... '. . ... • • • • • 

In summary, despite extensive efforts the mint industry has not been able tJttessfu y • 

find an adequate replacement for pyridate (Tough herbicide) to provide postemergence! • • • • • 

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weed control that does not cause significant injury to the mint crop. Therefore, weed 

control remains an urgent situation challenging the ability to produce high quality mint oil. 

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

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

increased demand for double-cut 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 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 from Oregon State University are attached 

since Indiana trial data was not recovered. A letter of support from Dr. Steve Weller, Purdue 

University is attached to help explain the benefits and usability of Tough in mint production. Dr. 

Weller has been instrumental in weed control research in Midwest mint production for three 

decades. 

Tough 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 is the only known broadleafherbicide that can 

provide post-emergent control of weeds without impacting crop yield. 

7. Residue Information 

Residue trials for mint were conducted by the lR-4 Program in 1994. Applications made in 

accordance with the requested provisions are not expected to result in residues of pyridate and its 

metabolites in excess of0.2 ppm for peppermint and spearmint tops. These tolerances have been 

established by the EPA and are recorded under CFR 180.462. Secondary residues in meat, 

poultry, and eggs are not expected to result. 

8. Risk Information 

On May 3, 2000 the EPA established tolerances of0.2 ppm for residues ofpyridate and its 

metabolites inion peppermint and spearmint tops. fnformation regarding pyridate toxicology and 

aggregate exposure can be found in the final rule published in the Federal Register May 3, 2000, 

volume 65, number 86, pages 25647-25652 (attached). 

a. Human Health 

Tough 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 LD50 for •••• rabbits is> 2,000 mg/kg. Inhalation LC50 >4.37 mg./Lair. Primary derm VJ~ tion •• :. 

study indicated it is mildly irritating to rabbit skin (EPA Health Effects zy is~rt ofthe • 

Office of Pesticide Programs, 2000). • • 

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The EPA concluded that residues of pyridate in drinking water do not contribute '·' .... • 

significantly to the aggregate acute human health risk. The acute human ea~h "rjsks • • •: 

resulting from exposure to pyridate in food and water are below EPA's le"~ concer-.'1 • 

for all population subgroups. As for chronic risk, the EPA also concluded that no harm • • • •• • J t I 

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will result from aggregate chronic exposure. 

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. 

The product label addresses the risks to worker/applicator by outlining handler 

precautions and required personal protective equipment. 

b. Potential to be found in drinking water 

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

low water solubility (1.5mg/L at 20 C), strong soil adsorption (Kd = .3-26) 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. 

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 fami ly 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 Jasper, Kosciusko, LaGrange, La Porte, Newton, Porter, Pulaski, Stark, anti' • • 

St. Joseph are listed in the attached table. :•• • 

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The use of Tough herbicide in accordance to the label in mint fields should not pose a. ••• 

• • risk to any threatened or endangered species. • • • • 

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• • • • f. Beneficial Organisms • 

Tough is not toxic to bees and other beneficial insects (i.e. lady beetles, predatory mites) .• 

See the attached EPA Environmental Fate and Effects Division (EFED) report. : • • • • • 

g. Fish and Aquatic Organisms 

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Pryridate is considered toxic to estuarine organisms. However, due to its strong soil 

adsorption and short half-life, if applied according to the label it should not pose a risk to 

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estuarine organisms (see attached EPA EFED report). The label states that this material 

should not be app lied within l 00 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. Coordinate with Other Agencies 

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

copy ofthis request. Any comments received will be forwarded to the U.S. EPA. 

10. Notification of Registrant 

Belchim Crop Protection has been notified and their letter of support is attached. In 

addition, Engage Agro USA Corp. is the U.S. distributor and they have also been notified. A 

letter of support from Engage Agro USA is also attached. 

11. Enforcement Program 

The Office of the Indiana State Chemist (OISC) has adeq uate authorities for enforcing 

provisions ofSection 18 emergency exemptions. OISC will require the registrant (or 

manufacturer, if unregistered) of Tough herbicide, Belchim Crop Protection, to prepare and 

make ava ilable to end users supplemental labeling that complies with OISC 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 OISC a report summarizing results of the emergency use after the end of the use period. 

12. Repeat Uses 

Tough has been previously used under a Section 18 from 1999-2000. Tough was later 

registered under an SLN 24c from 200 1-2007 after tolerances were established in 2000. 

13. Progress Toward Registration 

Registration and tolerance were established through the IR-4 by the EPA in May of2000. 

The Final Rule was published in the Federal Register vol. 65, No. 86, May 3, 2000 pages 25647-

25652 (attached). Tolerances were established for peppermint and spearmint tops at 0.20 ppm 

(CFR 180.462). Product registration was voluntarily cancelled by the registrant (Syngenta) aoo • • 

• • the product was no longer marketed in the U.S. Recently, Belchim Crop Protection acquired rt~ • 

marketing rights for pyridate from Syngenta. It is understood that Belchim is working with the: • • • 

EPA to re-register Tough in the U.S. • • •: 

B. Summary of Economic Loss 

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• •••• 1. Pest(s) to be Controlled • 

The pests causing an emergency are broadleafweeds, in particularly Redroot Pigweed, • 

Armaranthus retroflexus and Kochia, Kochia scoparia. : • • • • • 

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2. Discussion of the Emergency Condition 

This request is due to the emergency condition existing in mint from the postemergence 

of pigweed, kochia, and other broad leaf weed communities that cannot be effectively controlled 

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in active growing mint crops. All crops including mint suffer yield losses from o ulations of 

weeds, but unlike other crops, the quality of mint oil also is a ecte y weeds. A quality 

il13rketable mint crop is dependent upon weed free fields. 

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

created ar non-routine situation that poses additional stress on the need for ade uate 

postemergence roa ea wee con ro . Preemergence herbicides applied in February/early 

March to dormant mmt d1ss1pate to low levels tliat no longer control weeds after 4-6 weeks. The 

mint o cano su resses any new weed emer ence or establishment after this eriod. oncethe mint canopy is removed with a m1 to late June harvest (first cuttin , new weed shes 

L.>.LU~w. ese n us es me ude 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. 

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 ofmenthofuran 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 doublecut mint, but the acreage to meet the demand is not adequate due to management challenges 

ana~m t_cha ll enge facing dou e-cu pro uct10n. ro ucers do not have viable broadleaf 

weed control options to address th1s challenge. 

--- Redro~ present in mim at 1.6 weeds/yd2 renders mint oil unmarketable, due to 

off-flavors imparted during the distillation process (attachment). OSU research also 

demonstrated that a redroot pigweed infestation of I 0 plants/ft2 caused a peppermint oil yield 

reduction 34.4 lbs/acre, a 46% reduction (attached). Furthermore, both redroot and prostrate (A. 

blitoides) pigweeds have developed terbacil resistant biotypes. 

Kochia, a summer annual, can reach heights of six feet high and several feet in diameter, 

hindering harvest operations and competes for nutrients and light. In addition, an infestation Qf: •• 

2.3 kochia plants/ft2 can reduce mint oil yields by over 30% (attachment) in addition to reduCing• • 

oil quality. : • • • 

Mechanical tillage is not a post emergence 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 (Sinb<fr :jll •• • 

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 resismf1t • 

biotypes. 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 meth el uf! • 

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 post-emergent means of controlling these weeds in mint. 

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

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emergent broad leaf weed herbicides that are safe to the crop. ~has proven to be effective 

on broadleafweeds as well as possesses acceptable post-emergence crop safety needed for mint 

production. Populations of problem weeds have reached economically devastating levels and is 

impacting the producer's ability to compete in the market. Additionally, the recent increased 

, demand for double-cut mint has forced production into and created a non-rouft ne situation for 

~rod ce s who have no effective and viable postemergence broad leaf weed control options. 

The use ofTough 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. Additional Benefits Information 

4. Discussion of Economic Loss 

Redroot Pigweed/Kochia and broadleafweed communities have become serious weed 

pests of mint growers in Indiana. The lack of any post emergent weed control option, (no 

effective registered herbicide, and the presence of herbicide resistant pigweed) have created an 

emergency situation for Indiana mint growers. Furthermore, the recently 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). Kochia and Redroot Pigweed are often found in 

complexes of other weeds, which further reduces the yield and quality of mint oil. 

Five-Year History of Indiana Production 

Year 

2011 

2012 

2013 

2014 

2015 

Average 

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2. 

3. 

Average 

Yield 

(lbs I acre) 

71 

56 

54 

49 

58 

58 

Average Gross 

Price Revenue 

($I lb) ($I acre) 

$21 $1,495 

$21 $1,179 

$21 $1,140 

$21 $1,033 

$21 $1,208 

$21 $1,211 

Cost of Net 

Production Revenue 

($I acre) ($I acre) 

$1,100 $395 

$1,100 $79 

$1,100 $40 

$1,100 ($67) 

$1,100 $108 

$1,100 $111 

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Tier 2 Analysis 

A Tier 2 Significant Economic Loss (SEL) analysis illustrates the reduction of oil yield 

and quality as well as the loss of gross revenue due to the devaluation of tainted oil resulting 

from weed contaminants. The yield comparison reflects a 35% yield reduction (OSU trial data) 

on the portion ofthe acres (80%) faced with the impact of post-emergent weed control 

challenges. 

Furthermore, the yield calculations are based on the five-year average (20 11 -15) of 58 

lbs/acre. As previously stated in this request, the estimated acreage of Indiana mint is 14,000 

acres and approximately 11 ,200 acres (80%) would be treated with Tough herbicide. 

As for marketable oil quality, i_!:,is estimated that the use of Tough herbicide wou ld 

increase pure quality oil by 20%, thus reducing the amount of tainted devalued oil b the same. 

e eva uat10n o tainted oil ranges from a sma ll percentage deduction to complete 

rejection/loss. Based on industry knowledge, an average devaluation of35% 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 $8Million to the mint producers in Indiana. 

Tier 2 Indiana Economic Analysis of Yield and Quality Loss 

Baseline Emergency Change %Change 

Yield (lbs/acre) 1,161,785 812,000 -349,785 -30% 

Pure(% of yield) 90% 70% 

(lbs/acre) 1,045,606 568,400 -477,206 -46% 

Tainted(% of yield) 10% 30% 

(lbs/acre) 116,178 243,600 127,422 110% 

Price, Pure ($/lb) $21.00 $21.00 • ••• 

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Price, Tainted ($/lb) $13.65 $13.65 •••• 

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••• Gross Revenue ($/acre) $23,543,565 $15,261,540 -$8,282,025 -35% •••• 

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