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APPENDIX A

Testing of Tank Mix Products

1. Products proposed for tank-mixing with Enlist Duo may be added to the list of products that will 

not adversely affect the spray drift properties of Enlist Duo contained on the web site if a study is 

performed under the testing conditions set forth below; the test information is reported as set forth 

below; and the results are interpreted as set forth below and the interpretation supports adding the tested 

product to the list of products that will not adversely affect the spray drift properties of Enlist Duo:

Testing Conditions

Spray chamber test using conditions described in ASTM E-2798-11; or Wind Tunnel test using 

conditions described in EPA Final Generic Verification Protocol for Testing Pesticide Application Spray 

Drift Reduction Technologies for Row and Field Crops (September 2013)

Testing Media: Enlist Duo and Enlist Duo + Proposed Tank Mix Product

Test Nozzle: AIXR 11004 at 40 psi

Number of Replicates: 3 for each tested medium

Reporting

Validation information as summarized in Appendix B

Full droplet spectrum to be reported for each replicate of each tested medium

Perform AGDISP (8.26) modeling run for each replicate droplet spectrum for each tested medium 

(AGDISP input parameters described in Appendix C)

Establish 30 foot spray drift deposition estimate from AGDISP run on each replicate for each tested 

medium

Establish mean and standard deviation of 30 foot deposition for the 3 replicates of each tested medium

One-tail (upper bound) t-test (p=0.1) to determine if proposed tank-mix product is above Enlist Duo 30 

foot spray drift deposition

Interpretation of Results

If mean 30 foot deposition for proposed tank-mix product is not statistically greater than mean 30 foot 

deposition for Enlist Duo, proposed tank-mix product can be added to the list of products that will not 

adversely affect the spray drift properties of Enlist Duo contained on the web site. If mean 30 foot 

deposition for proposed tank-mix product is statistically greater than mean 30 foot deposition for Enlist 
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Duo, proposed tank-mix product cannot be added to the list of products that will not adversely affect the 

spray drift properties of Enlist Duo contained on the web site

2. Results from other testing protocols will be acceptable for adding products to the list of products 

that will not adversely affect the spray drift properties of Enlist Duo provided that EPA has determined 

in writing that such other protocol is appropriate for such purpose.
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APPENDIX B

Validation Criteria

a. Detailed information of instrument setting and measurements

‐ The distance from the nozzle tips to the laser settings

‐ Measurements of airspeed and flow rate of liquid

b. Detailed information of test substances

‐ Volume composition and density of Enlist formulation (2,4‐D choline and glyphosate) and tank mixes

c. Summary of the entire spray output distribution for each nozzle/tank mixes with statistical analysis of 

replicates.

d. Graphical outputs of Sympatec Helos laser diffraction particle size analyzer FOR individual spectrum 

Report of Dv0.1 (SD), Dv0.5 (SD), and DV0.9 (SD) as well as mean % fines of (≤ 141μm SD) fractions
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APPENDIX C

AGDISP Input Parameters

Parameter Value comments 

Application method section

Method Ground 

Nozzle type Flat fan (Default) The direct use of the DSD 

overrides the use of “Nozzle type. 

Boom pressure 40 psi If nozzles/tank mixes were tested 

at 40 psi. It has to be consistent 

with tank mix as well as Enlist 

for both TeeJet and AIXR 

nozzles.

Release height 3 ft Default 

Spray lines 20 Default 

Meteorology section

Wind type Single height Default 

Wind speed 15 mph Under bound from label 

Wind direction -90 deg Worst-case and default 

Temperature 65 F Default 

Relative humidity 50% Default 

Surface section

Angles 0 Default 

Canopy None Default 

Surface roughness 0.12 ft Mean of “crops” cover type 

Application technique section

Nozzles 54, even spacing Standard boom setup 

DSD From wind tunnel results, 

imported in library 

Atmospheric stability Strong Default 

Swath section
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Swath width 90 ft Standard boom 

Swath displacement 0 ft Worst-case 

Spray material section

Spray volume rate 15 gal/acre From Enlist Duo label 

Volatile/nonvolatile 

fraction 

Enlist Duo at 2.8% v/v To calculate volatile/nonvolatile 

fraction in the tank mix for the 

model input, provide detailed 

information of the tested 

formulations and tank mixes. 

See sample calculation below 

used in WT study submitted by 

DOW (MRID 49384801)1 

1The tested mixture was 2.8% (v/v) Enlist Duo in water. Enlist Duo has a density of 1.171 kg/L

and contains 24.42 % (w/w) of 2,4-D choline salt (16.65% (w/w) 2,4-D acid equivalent) and

22.17% (w/w) glyphosate dimethylammonium salt.

For example, a 100-liter batch would contain the following:

Enlist Duo 2.8% * 100 L = 2.8L; 2.8L * 1.171 kg/L = 3.279 kg

Water: 100 -2.8 L = 97.2 L = 97.2 kg

Total weight: 3.279+97.2 = 100.497 kg

Active ingredient fraction: 3.279 kg * 16.65 % (a.e.) = 0.546 kg; 0.546 kg/100.497 kg = 0.0054 (dimensionless)

Non-volatile fraction: 3.279 kg* (24.42 % + 22.17%) = 1.528 kg; 1.528 kg/100.497 kg = 0.0152 (dimensionless)
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APPENDIX D

Herbicide Resistance Management Plan

Dow AgroSciences (DAS) must:

A. Grower Agreements, Field Detection and Remediation Components:

1. Ensure that any person who purchases any Enlist seed sign a binding contract, enforceable by 

DAS, herein referred to as a “grower agreement.” In such grower agreement, DAS will reinforce 

with users of Enlist Duo the critical importance of following resistance management practices. 

This includes stressing the need for pre- and post-application field scouting and that lack of 

herbicide efficacy should be reported promptly to DAS or its representative.

2. Provide a copy of the grower agreement to EPA;

3. Retain copies of all executed grower agreements for a period of 3 years from the date of 

execution, and make such copies available to EPA upon request;

4. If any grower informs you of a lack of herbicide efficacy, then you or your representative must 

make an effort to evaluate the field for “likely resistance” to Enlist Duo by applying the criteria 

set forth in Norsworthy, et al., “Reducing the Risks of Herbicide Resistance: Best Management 

Practices and Recommendations,” Weed Science 2012 Special Issue:31–62 (hereinafter

“Norsworthy criteria”);

5. Keep records of all field evaluations for “likely resistance” for a period of 3 years, and make 

such copies available to EPA upon request; and

6. If one or more of the Norsworthy criteria are met, then:

a. Provide the grower with specific information and recommendations to control and 

contain likely resistant weeds, including retreatment and/or other non-chemical controls, 

as appropriate. If requested by the grower, DAS will become actively involved in 

implementation of weed control measures;

b. Request, at the time of the initial determination that one or more of the Norsworthy 

criteria are met and prior to any application of alternative control practices, that the 

grower provide you with access to the relevant field(s) to collect specimens of the likely 

resistant weeds (potted specimens or seeds) for further evaluation in the greenhouse or 

laboratory, and so collect such specimens if possible (or, alternatively, request that the 

grower provide such specimens to you, at your expense);

c. Commence greenhouse or laboratory studies to confirm resistance as soon as practicable 

following sample collection;
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d. To the extent possible, contact or visit the grower in an appropriate timeframe after 

implementation of the additional weed control measures in order to evaluate success of 

such measures; and

e. If the additional weed control measures were not successful in controlling the likely 

resistant weeds, then:

i. Work with the grower to determine the reason(s) why the additional control 

measures were not successful;

ii. Report annually the inability to control the likely resistant weeds to relevant 

stakeholders; and

iii. Offer to further assist the grower in controlling and containing the likely resistant 

weeds, including retreatment and/or other non-chemical controls, as appropriate.

B. Educational / Informational Component:

1. Develop and implement an education program for growers that includes the following elements:

a. The education program shall identify appropriate best management practices (BMPs), set 

forth under “Best Management Practices (BMPs) Component,” below, to avoid and 

control weed resistance, and shall convey to growers the importance of complying with 

BMPs;

b. The education program shall include at least one written communication regarding 

herbicide resistance management each year to purchasers of Enlist seed (separate and 

apart from the grower agreement document); and 

c. You must make the education program available to DAS sales representatives for 

distribution to growers.

2. Provide to EPA the original education program within three months of the issuance of this 

registration.

C. Evaluation Component:

1. Annually conduct a survey of users of Enlist seed. This survey must be based on a statistically 

representative sample of users of Enlist seed. The sample size and geographical resolution 

should be adequate to allow analysis of responses within regions, between regions, and across 

the United States. This survey shall evaluate, at a minimum, the following:

a. Growers’ adherence to the terms of the grower agreements, and
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b. Whether growers have encountered any perceived issue with non-performance or lack of 

efficacy of Enlist Duo and, if so, how growers have responded.

2. Utilize the results from the survey described in paragraph 1 of this section to annually review, 

and modify as appropriate for the upcoming growing season, the following:

a. Efforts aimed at achieving compliance with the grower agreement;

b. Responses to incidents of likely resistance and confirmed resistance; and

c. The education program. At the initiative of either EPA or DAS, EPA and DAS shall 

consult about possible modifications of the education program.

D. Reporting Component:

1. Submit annual reports to EPA by January 15th of each year, beginning on January 15, 2016. 

Such reports shall include:

a. Annual sales of Enlist seed and Enlist Duo herbicide by state;

b. The current grower agreement;

c. The first annual report shall include the current education program and associated 

materials, and subsequent annual reports shall include updates of any aspect of the 

education program and associated materials that have materially changed since 

submission of the previous annual report;

d. Summary of your efforts aimed at achieving compliance with the grower agreements;

e. Summary of your determinations as to whether any reported lack of herbicide efficacy 

was “likely resistance,” your follow-up actions taken, and, if available, the ultimate 

outcome (e.g., evaluation of success of additional weed control measures) regarding each 

case of “likely resistance.” In the annual report, DAS will list the cases of likely 

resistance by county and state.

f. The results of the annual survey described in paragraph 1 under “Evaluation 

Component,” above, including whether growers are implementing herbicide resistance 

BMPs, and a summary of your annual review and possible modification – based on that 

survey – of the education program, grower agreement compliance efforts, and response to 

reports of likely resistance, described in paragraph 2 under “Evaluation Component,” 

above; and

g. Summary of the status of any laboratory and greenhouse testing performed by, or at the 

direction of, Dow AgroSciences following up on incidents of likely resistance, performed 
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in the previous year. Data pertaining to such testing need not be included in the annual 

reports, but such data must be made available to EPA upon request.

2. Following your submission of the annual report, you shall meet with the EPA at EPA’s request 

in order to evaluate and consider the information contained in the report.

E. Best Management Practices (BMPs) Component:

1. Best management practices (BMPs) must be identified in your education program. You must 

advise growers to follow them in your grower agreements. The following are examples of 

BMPs:

a. Regarding crop selection and cultural practices:

i. Understand the biology of the weeds present.

ii. Use a diversified approach toward weed management focused on preventing weed 

seed production and reducing the number of weed seeds in the soil seed-bank.

iii. Emphasize cultural practices that suppress weeds by using crop competitiveness.

iv. Plant into weed free fields, keep fields as weed free as possible, and note areas 

where weeds were a problem in prior seasons.

v. Incorporate additional weed control practices whenever possible, such as 

mechanical cultivation, biological management practices, crop rotation, and 

weed-free crop seeds, as part of an integrated weed control program.

vi. Do not allow weed escapes to produce seeds, roots or tubers.

vii. Manage weed seed at harvest and post-harvest to prevent a buildup of the weed 

seed-bank.

viii. Prevent field-to-field and within-field movement of weed seed or vegetative 

propagules.

ix. Thoroughly clean plant residues from equipment before leaving fields.

x. Prevent an influx of weeds into the field by managing field borders.

xi. Fields must be scouted before application to ensure that herbicides and 

application rates will be appropriate for the weed species and weed sizes present.

xii. Fields must be scouted after application to confirm herbicide effectiveness and to 

detect weed escapes.
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xiii. If resistance is suspected, treat weed escapes with an alternate mode of action or 

use non-chemical methods to remove escapes.

b. Regarding herbicide selection:

i. Use a broad spectrum soil applied herbicide with a mechanism of action that 

differs from this product as a foundation in a weed control program. 

ii. A broad spectrum weed control program should consider all of the weeds present 

in the field. Weeds should be identified through scouting and field history.

iii. Difficult to control weeds may require sequential applications of herbicides with 

alternative mechanisms of action.

iv. Fields with difficult to control weeds should be rotated to crops that allow the use 

of herbicides with alternative mechanisms of action.

v. Apply full rates of this herbicide for the most difficult to control weed in the field. 

Applications should be made when weeds are at the correct size to minimize weed 

escapes.

vi. Do not use more than two applications of this herbicide or any herbicide with the 

same mechanism of action within a single growing season unless mixed with 

another mechanism of action herbicide with overlapping spectrum for the difficult 

to control weeds. 

vii. Report any incidence of lack of efficacy of this product against a particular weed 

species to Dow AgroSciences or a Dow AgroSciences representative.

This list may be updated or revised as new information becomes available.