DuPont Response to the EPA’s “Proposed Registration of Aminocyclopyrachlor on Non-Crop Areas, Sod Farms, Turf, and Residential Lawns” Compiled by Rebecca M. Ashley July 16, 2010

DuPont has applied for the initial registration of the active ingredient aminocyclopyrachlor, and associated e nd-use products, for use in the non-crop, vegetation management (VM) market. As part of the review process for this registration action, the Agency has posted a number of documents to the public docket (EPA-HQOPP-2009-0789-0011) for review and comment. Pr esented here are DuPont’s initial comments to the Agency document titled “Proposed Registration of Aminocyclopyrachlor on Non-Crop Areas, Sod Farms, Turf, and Residential Lawns”. That document includes the following pr oposed label language for the vegetation management end-use products:

In order to mitigate risk to non-target plants and keep the pesticide on the intended treatment area, the following sp ray drift language must be placed on all aminocyclopyrachlor end-use product labels

Products Primarily Intended for Commercial Use on Non-Crop Areas

Aerial Application Restriction

“When applying by air, maintain a 50-foot buffer around non-target aquatic areas and between the point of direct application and the closest downwind edge of non-target terrestrial areas . Apply only using nozzles which will deliver coarse or greater (VMD >350 microns) droplets as defined by ASABE S572 standard. Do not release spray at a height gr eater than 10 feet abo ve the ground or crop canopy unless a greater height is required for aircraft safety. Do not apply when wind speed is greater than 10 mph. Do not apply during a temperature

inversion.”

Ground Application Restriction

“When applying by ground, maintain a 50-foot buffer around non-target aquatic areas and between the point of direct application and the closest downwind edge of non-target terrestrial areas. Apply only using nozzles which will deliver coarse or greater (VMD >350 microns) droplets as defined by ASABE S572 standard. Do not apply with a nozzle height grea ter than 4 feet above the ground or crop canopy. Do not apply when wind speed is greater than 10 mph. Do not apply during a temperature inversion.”

For several reasons discussed below, DuPont be lieves that the stated buffers to non-target aquatic areas and non-target terrestrial areas are not necessary to mitigate off-target

1movement of aminocyclopyrachlor end-use pr oducts used in vegetation management programs. Specifically:

1. The Agency’s estimate of possible off-target movement of aminocylopyrachlor applications is ba sed on laboratory data from the terrestrial plant studies combined with extrapolations from models including Terrplant and AgDrift. DuPont believes that the use of these laboratory data and the models results in gross overestimates of possible off-target movement,

and calculated or recommended buffers.

2. Applications of aminocyclopyrachlor end-use products will be made by applicators using modern spray e quipment under application conditions designed to reduce off-target movement . In addition, these applicators are typically required to under go training that includes instructions on reducing possible off-target movement of herbicides during their application.

3. Addition of buffers to aminocyclopyrach lor end-use products will result in lessened utilization of the products, and will force land use managers to continue to use older, more problematic products to attempt to control weeds.

4. Aminocyclopyrachlor offers unprecedented control of a large number of weeds - including many invasive and noxious weed species that are currently not being optimally controlled. The addition of the buffer for aminocyclopyrachlor end-use products wi ll consequently result in reduced control of these important weed species.

DuPont understands and supports the Agency’s e ffort to minimize any potential off-target movement of aminocyclopyrachlor containi ng end-use products which, in turn, will mitigate possible effects on non-target plant spec ies. DuPont believes that this can be accomplished through the best management practices that are currently in place in the vegetation management industry. Therefore, as an alternative to EP A’s suggested buffers to non-target terrestrial and aquatic areas, DuPont is herein proposing label language, similar to that found on current vegetati on management products, for the relevant Aminocyclopyrachlor end-use products. DuP ont believes that this language, combined with other recommended restrictions, will provide adequate margins of safety to terrestrial and semi-aquatic plants for Aminocyclopyrachlor uses.

Current Modeling and Risk Assessment Resu lts– Overestimation of Risk

Terrplant and AgDrift Modeling

Comments on Terrplant:

The EECs calculated from Terrplant modeling an d the subsequent inputs into the AgDrift model result in a large overestimate for th e need for buffers for aminocyclopyrachlor

2end-use products. Refined modeling using appropriate vegetation management use scenarios for aminocyclopyrachlor end-us e products demonstrate a much lower likelihood of spray drift from both ground and ae rial application than that demonstrated by using the AgDrift model (which is more appr opriate to agricultural crop applications). Extrapolation from existing data also demonstrates that the likelihood of aminocylopyrachlor residues being found in wate rs that might be used for irrigation,

which could result in risk to non-target plants, is low.

The EPA has assessed the potential risk fr om applications of aminocyclopyrachlor to non-target plants growing in semi-aquatic habitats by utilizing the risk assessment strategy developed and implemented through the model Terrplant version 1.2.2. This model assessed an application to bare so il at a rate of 0.284 lb ai/acre by ground and aerial spray equipment for non-crop use. Th e model assumes a runoff value of 10% of the applied product based on the solubility of aminocyclopyrachlor. The model scenario

also assumes channelized flow and eventu al deposition of the runoff from a 10 acre application area to a 1 acre lo w lying semi-aquatic area. It further assumes an additional environmental loading of 1% of the applied rate for ground application and 5% for aerial application as a result of spray drift. The resulting total estimated environmental concentrations (EEC) for aminocyclopyrachlor applied at the maximum use rate for noncrop uses (0.284 lb ai/acre) was 0.14484 lb ai/acre and 0.1562 lb ai./acre for ground and aerial applications, respectively.

The Terrplant assessment endpoints were deri ved from the pre-emer gent terrestrial nontarget plant studies (soil emergence and vegetative growth). The ER25 and NOAER for the most sensitive monocot and dicot species are the most appropriate endpoints for assessment. In semi-aquatic areas, the Te rrplant risk quotients (RQs) calculated by the Agency for monocot species for non-listed and listed species are 3.7 and 3.0 respectively. The Terrplant RQs for dicot species are 273 for non-listed species, and 295 for listed species. (Table 5.2 of the EFED assessment dated January 22, 2010.) These values are derived from ground application. Aerial RQ s are proportionally higher, based on the higher drift level of 5%.

We believe, however, that the Te rrplant scenario used to ev aluate risk to semi-aquatic plant species is not appropriate for non-cr op vegetation management applications since that model is based primarily on conditions t ypical of crop use. Aminocyclopyrachlor at

the maximum labeled rate will be used fo r more localized app lication, and for linear applications along railroad, hi ghway, and other types of right s-of-ways, as proposed for registration. Unlike applicati ons to cropland, vegetation ma nagement applications are characterized by narrow swath applications over consider able linear distance. For example, a linear application with a swath widt h 25 feet would require over three miles of linear distance to treat the equi valent of 10 acres of right-o f-way. Any runoff from that

25 foot x 3 mile treated area would not be e xpected to flow into a single 1 acre pond or semi-aquatic area. Further, thes e applications are made by hi ghly trained operators with equipment specifically designed to eliminate o ff-site movement through spray drift. In addition to the spatial considerations, heav ily vegetated zones typically border the

3application areas and would serve to reduce ru noff and channelized flow from the treated areas, thus further reducing the exposure to off-target semi-aquatic habitats.

For these reasons, we would propose that the runoff scenario/assessment to dry areas is more appropriate to assess the propos ed vegetation management uses of aminocyclopyrachlor – recognizing that it ma y still overestimate actual exposure at

distance due to the narrow sw ath width and the degree of vegetative cover found in vegetation management applications. Such an assessment resulted in RQ values for monocot species for non-listed and listed species of 0.43 and 0.36 respectively. The Terrplant RQs for dicot species are 32 for non- listed species, and 35 for listed species. These values are derived from ground applic ation. Aerial RQs, as noted above, are proportionally higher based on the higher drift level of 5%.

Therefore, based on the above considerations , we believe that a buffer to non-target aquatic areas for VM applications of aminocyclopyrachlor is not warranted.

Comments on AgDRIFT:

The proposed label statements regarding nozzles, release hei ght, wind speed and temperature inversions are consistent with pr actices that are commonl y used in vegetative management applications and are generally accepted best practices for aerial applications.

The buffer requirement, however, is impractical since many of the use sites will be along rights-of-way, and the proposed 50-foot buffer would have the effect of prohibiting some key uses for this product. For example, rights-of-way may be only 50 feet wide along railroads or power lines, and applications to roadsides may be restricted to 20 feet on either side of the roadway. Rights-of-way c ould not be treated effectively since the nontarget areas would be immediately adjacent to the site, and would require an on-site buffer that is actually greate r than or equal to the widt h of the treated area.

Aerial Application

To minimize drift from applications to rights-of-way, many aerial applicators have adopted spray technologies that deliver ultr a coarse droplet size distributions (VMD > 1000) using high volumes of spray solutions. Using slow speed helicopters in light winds, these applications would require no buffe rs to minimize the potential for off-target effects on terrestrial plants . The drift modeling conducte d by EPA provides a useful starting point for further analys is which illustrates the low risk to non-target areas from VM applications with the low drift nozzles.

The default AgDRIFT model input parameters were designed to simulate deposition from typical agricultural applications and, consequently, assu me a larger number of flight lines (or swaths) and droplet size dist ributions that are not typical of applications to rights-ofway (ROW). Modeling inputs typical of RO W are shown in Table 1 and compared to EPA model inputs. While the AgDRIFT m odel is not overly robust to assess VM applications, we have forced alternative inputs for typical vegetation management use

4scenarios with coarse droplet size using a single flight line into that model to simulate an application to a right-of-way with a swath width of 60 feet . [Note, however, that swath widths in VM applications are generally less than 60 feet.] Typical application conditions in vegetation management reduc e the need for buffers, and the following assessment adjusts the modeling inputs to simu late the different vegetation management application scenario.

Table 1. Inputs for AgDRIFT - Aerial VM applications

Original EPA inputs used by

EFED EPA proposal - requirement for coarse droplet size ROW fixed wing

VM scenario ROW rotary wing VM

scenario AgDRIFT Tier II or III III III III

Aircraft Slow fixed wing Slow fixed wing Slow fixed wing Slow rotary Droplet size

distribution Very fine to fine Coarse Coarse Coarse

Application rate (lb ai/acre): 0.284 0.284 0.284 0.284

Non-volatile application rate (lb ai/acre): 0.568 0.568 0.568 0.568

Application volume (gals/acre): 10 10 10 10

Swath displacement

fraction 0.6505 0.2489 0.2489 0.2489

Flight lines (number of application swaths) 20 20 1 1

Wind speed (mph) 10 10 10 10

The buffers calculated by AgDRIFT using the EPA inputs for very fi ne to fine droplet size ranged from about 108 feet (monocot seedling emergence endpoint) to >2640 feet (dicot vegetative vigor endpoint). However, as shown in Table 2 below, using the proposed requirement for a coarse droplet size distribution and simulating a ROW application with a single fli ght line (or swath), the calcula ted buffers are significantly reduced as compared to the results from the EPA modeling (ranging from 13 feet for monocot seedling emergence to 846 f eet for dicot vegetative vigor).

Table 2. Comparison of Calculated Buffer Distances to Attain a Risk Quotient at the EPA

LOC
Endpoint Fraction of applied EPA Modeling (very fine to fine droplets) EPA proposal – requirement

for coarse droplet size ROW Fixed wing, 1 swath, coarse droplet ROW Rotary wing, 1 swath, coarse droplet Seedling emergence,

monocots 0.169 108 ft. 23 ft. 16.4 ft. 13 ft.

Seedling emergence,

dicots 0.00187 >2640 ft. 1644 ft. 305 ft. 262 ft.

Vegetative vigor,

monocots 0.0204 1749 ft. 180 ft. 108 ft. 95 ft.

Vegetative vigor,

dicots 0.000264 >2640 ft. >2600 ft. 846 ft. 807 ft.

5Further modeling to simulate low drift alternativ es typically used in aerial application for vegetation management, i.e., using extremel y coarse droplet size distributions, shows dramatic reductions in modeled drift compared to coarse droplet size distributions. For example, the droplet size dist ribution for the Accuflo 028 noz zle is representative of similar extremely coarse droplet technologies , and was obtained from the SDTF library. For this modeling scenario the swath displa cement fraction was set to 0, which forces a higher deposition fraction at 0 feet than fo r simulations using the swath displacement fractions in AgDRIFT. The modeling inputs an d resultant calculated buffers are shown in Tables 3 and 4, respectively.

Table 3. Alternative Low Drift Mode ling Inputs for ROW applications

ROW fixed wing – extremely coarse droplet

scenario ROW rotary wing - extremely coarse droplet

scenario ROW rotary wing, low wind speed - extremely coarse droplet scenario AgDRIFT Tier III III III

Aircraft Slow fixed wing Slow rotary Slow rotary

Nozzle Accuflo 028 (VMD

1212 μ m, relative span 0.6915) Accuflo 028 (VMD

1212 μ m, relative span 0.6915) Accuflo 028 (VMD

1212 μ m, relative span 0.6915) Droplet size distribution Ex tremely coarse Extremely coarse Extremely coarse Application rate: 0.284 lb ai/ac 0.284 lb ai/ac 0.284 lb ai/ac Non-volatile application

rate: 0.568 lb ai/ac 0.568 lb ai/ac 0.568 lb ai/ac

Application volume: 10 gals/acr e 10 gals/acre 10 gals/acre Swath displacement

fraction 0.0 0.0 0.0

Flight lines (number of application swaths) 1 1 1

Wind speed (mph) 10 10 5

Table 4. Comparison of Calculated Buffer Distances to Attain a Risk Quotient at the EPA

LOC

Endpoint Fraction of applied ROW fixed wing – extremely coarse droplet ROW rotary wing - extremely coarse droplet ROW rotary wing, low wind speed - extremely coarse droplet Seedling emergence,

monocots 0.169 13 ft. 6.6 ft. 0 ft.

Seedling emergence,

dicots 0.00187 56 ft. 29.5 ft. 26 ft.

Vegetative vigor,

monocots 0.0204 33 ft. 13 ft. 6.6 ft.

Vegetative vigor, dicots 0.000264 135 ft. 111 ft. 82 ft.

As noted above, the buffers calculated by AgDR IFT using the EPA inputs for very fine to fine droplet size ranged from about 108 feet (monocot s eedling emergence endpoint) to >2640 feet (dicot vegetative vigor endpoint). However, as shown in Table 4, modeling the typical extremely coarse droplet size di stribution and simulating a ROW application

6with a single flight line (o r swath), results in calculated buffers that are significantly reduced (ranging from 0 feet for monocot seedling emergence to 135 feet for dicot vegetative vigor) as compared to the results from the EPA modeling.

Based on modeling for aerial applications us ing more realistic i nputs simulating typical vegetation management use scenarios, there are significant reductions in the calculation of buffers, which demonstrate that buffers s hould not be required for applications of aminocyclopyrachlor end-use products - especi ally when using low drift equipment and best management practices as proposed on the label.

Ground Application

Drift modeling for ground applications using AgDRIFT is limited by the data for the empirical relationships that the model is base d on. Of particular concern is that the deposition data only allow separation into two drop size categories and two application heights - which precludes the simulation of the coarse to extremely coarse drop size distributions that are common in ground ROW applications. However, within the framework of the AgDRIFT model, two for ced changes to the EPA modeling scenario are possible to simulate ROW applications: 1) reduce swaths from 20 to 1, and 2) select fine to medium/coarse drop size category. Table 5 summarizes the base modeling scenarios and the ROW applica tion alternative scenarios.

Table 5. Inputs for AgDRIFT ground applications.

EPA inputs EPA proposal for

use of coarse droplets ROW Scenario I ROW Scenario II

AgDRIFT Tier I I I I Application height high high high high Droplet size

distribution Very fine to fine Fine to

medium/coarse Fine to

medium/coarse Fine to

medium/coarse

Percentile 90th 90th 90th 50th Application rate: 0.284 lb ai/ac 0.284 lb ai/ac 0.284 lb ai/ac 0.284 lb ai/ac

Number of Swaths 20 20 1 1

As shown in Table 6 below, utilizing the modeling changes noted above in Table 5 significantly reduces the calculated buffers as compared to the results from the EPA modeling. Specifically, calculated buffers ar e reduced from 16.4 feet to 3.3 feet for monocot seedling emergence, and from >1000 f eet to 282 feet for dicot vegetative vigor.

7Table 6. Comparison of Buffer Distances to Attain a Risk Quotient at the EPA LOC (Ground Applications)

Endpoint Fraction of applied EPA Modeling, very fine to fine

droplets, 90 th
percentile curve EPA proposal - Requirement for coarse droplets ROW 1 swath,

90 th
percentile

curve ROW 1 swath, 50 th

percentile

curve

Seedling

emergence,

monocots 0.169 16.4 ft. 3.3 ft. 3.3 ft. 3.3 ft.

Seedling emergence, dicots 0.00187 833 ft. 453 ft. 102 ft. 79 ft.

Vegetative vigor,

monocots 0.0204 121 ft. 26 ft. 16 ft. 16 ft.

Vegetative vigor,

dicots 0.000264 >1000 ft. >1000 ft. 394 ft. 282 ft.

Although not specifically appropriate for assessing ROW applications, AgDRIFT modeling for ground applications using more realistic inputs simulating typical vegetation management use scenarios still results in significant reductions in the calculated buffers, and demonstrates that buffe rs should not be required for applications of aminocyclopyrachlor end-use products - es pecially when using low drift equipment and best management practices as proposed on the label.

Logistics of Vegetation Ma nagement Applications and Impracticality of Buffers

The requirement of buffers for aminocyl opyrachlor end-use products for use in vegetation management would severely limit, or even prohibit, the use of the products in

these markets. Feedback received from th e Railroad industry, vari ous state Departments of Transportation (DOTs), and commercial applicators indicates that buffers are impractical for utility rights-of-way, road sides and other vegetation management use sites, and are inconsistent with the goals of weed control programs. Current practices, combined with advances in application t echnology and stewardship training in these market segments, address the concern for re ducing off-target move ment of pesticide applications. Reducing off-target movement is important to vegetation managers for a number of reasons, including the reduction of pesticide exposure to workers, residents and animals, and limiting any damage to susceptible crops or other desirable plants. In addition, applicators are keenly aware of the added cost to their bus iness if off-target movement occurs. Applicators have many options available to them to reduce off-target movement of their applications including selection of the proper application equipment, nozzle type, application height and operating pressure. In addition, they also have a strong awareness of the effects of wind direc tion and other weather effects (temperature, humidity) on possible off-target movement of pesticide applications. Further, drift retardants are also commonly used in these applications.

Feedback from the VM industry indi cated that specifying buffers on aminocyclopyrachlor end-use products would be problematic in this market. Howard

8Peavey, Alabama DOT Senior Agronomist, i ndicated that “buffers would likely reduce efficiencies by requiring return trips to certain routes or result in ar eas that did not receive

treatment. 1 Lines of sight may not be cleared as effectively and a ppurtenance protection may not be as efficient - po ssibly resulting in increased co st to tax payers”. Rand Swanigan, Roadside Management Specialis t for the Missouri DOT, noted that the “majority of roadside right of way is very narrow and buffer areas would result in most areas being untreated - resulting in incr eased populations of noxious, invasive and problematic weeds.” 2 Richard M. Loughery the Director of Environmental Activities for Edison Electric Institute (EEI) provided th e following comments regarding the possible requirement of buffers and the subseq uent impact on electric utilities:

“The application of buffer zones would be likely to severely diminish the ability of electric utilities to fully utilize integrated vegetation management (IVM). The environmental benefits of IVM are documented by over 60 years of research (Bramble & Byrnes in particular). EEI and member companies have participated in US EPA's Pesticide Environmental Stewardship Program (PESP). The PESP program has highlighted the electric utility industry's IVM practices. The no-spray buffer zone proposal seems to run c ounter to the PESP program. Utility rights-of-way can be part of the so lution for providing wildlife migration corridors and habitat for pollinators. However, an IVM approach including the spraying of herbicides is necessary to provide necessary habitat within the rights-of-way. M echanical clearing can be the most appropriate utility vegetation management in some cases, but not all. The proposed no-spray buffer zones w ould likely push utilities to use mechanical clearing more often to m eet the NERC reliability standards for rights-of-way vegetation management.” 3

Note that, in a public docket comment in re sponse to proposed buffers for sulfometuron methyl, Robert E. Fronczack, Assistant Vice President Environment & Haz Mat, for the

Association of American Railroads stated that “In order to safely and efficiently operate,

effective control of unwante d vegetation along the nation's railroad rights-of-way is vitally important. Unwanted weeds and brus h create safety and operational problems including; reduced visibility at grade crossi ngs and signals, fire hazards, difficulties with inspections, rail wheel slippage, as well as compliance problems with state and local weed abatement regulations.” Feedback from the Railroad industry indicates that the assignment of buffers to non-target terrestrial and aquatic areas woul d be impractical, and that the use of buffers in railroad applic ations “are unrealistic and will make products virtually unusable in our industry.” 4

1 Email from Howard Peavey, Sr. Agronomist Alabama DOT, to Doug Wood, DuPont, dated June 28,

2010.

2 Email from Rand Swanigan, Roadside Management Specialist Missouri DOT, to Doug Wood, DuPont, dated June 24, 2010.

3 Email from Richard Loughery, Director, Environmental Activities, Edison Electric Institute to Mark Rice, DuPont, dated June 28, 2010.

4 Comment to the public docket (EPA-HQ-OPP-2008-0 129-0167) by Robert E. Fronczack, dated February 3, 2009

9Gary Nyberg, Manager Vegetation Contro l, BNSF Railway, provided the following

comments:

“Requiring buffer zones for aerial applica tion would eliminate helicopter spraying on railroads. Helicopter application is an effective tool to ach ieve the goals and objectives of railroad weed control. Many areas of the railroad are not accessible with conventional ground equipment and th e use of helicopters is necessary to help comply with Federal and State vege tation and noxious weed laws that affect

railroads.” 5

Canadian PMRA – Decisions Regarding Ve getation Management Use Pattern

It is of significance to note that in a number of Re-evaluation Decision Documents, Canada’s Pest Management Re gulatory Authority (PMRA) ha s concluded that vegetation management uses are generally exempt from terrestrial buffers. In the re-evaluation decision document for 2,4-D (dated May 16, 2008) 6 , PMRA explained “The PMRA has exempted rights-of-way uses from requiring buffer zones to protec t terrestrial habitat because complete plant/weed control is require d right up to edge of the application areas on these sites to ensure user safety.” Some additional examples of this exemption are

listed below:

Re-evaluation Decisi on: Metsulfuron Methyl, November 10, 2008 7

For application to rights-of-way, buffer zones for protection of sensitive terrestrial habitats are not required; how ever, the best available application strategies which minimize off-site drift, including mete orological conditions (e.g. wind direction, low wind speed) and spray equipment (e.g. coarse droplet sizes, minimizing the height above canopy), should be used.

Buffer zones for the protection of terres trial habitats are not required for use on rights-of-way including railroad ballast, rail and hydro rights-of-way, utility easements, roads, and training grounds and firing ranges on military bases.

5 Email from Gary Nyberg, Manager Vegetation Control, BNSF Railway, to Dan Mixon, DuPont, dated July 1, 2010.

6 Re-evaluation Decision: (2,4-Dichlorophenoxy) acetic Acid [2,4-D]; http://www.hc-sc.gc.ca/cpsspc/pubs/pest/_decisions/rvd2008-11/index-eng.php

7 Re-evaluation Decision: Metsulfuron Methyl; http://www.hc-sc.gc.ca/cps-spc/pubs/pest/_decisions/ rvd2008-35/ index-eng.php

10Re-evaluation Decision : Dicamba, 5 August 2008 8

For application to rights-of-way, buffer zones for protection of sensitive terrestrial habitats are not required; however, the best available application strategies to minimize off-site drift, including mete orological conditions (e.g. wind direction, low wind speed) and spray equipment (e.g. coarse droplet sizes, minimizing height above canopy), should be used.

Buffer zones for the protection of terres trial habitats are not required for use on rights-of-way, including ra ilroad ballast, rail and hydro rights-of-way, utility easements, roads, and training grounds and firing ranges on military bases.

Re-evaluation Decision: Picloram, January 14, 2009 9

Buffer zones for the protection of terres trial habitats are not required for use on rights-of-way including railroad ballast, rail and hydro rights-of-way, utility

easements and roads.

For application to rights-of-way, buffer zones for protection of sensitive terrestrial habitats are not required; how ever, the best available application strategies that minimize off-site drift, including mete orological conditions (e.g. wind direction, low wind speed) and spray equipment (e.g. coarse droplet sizes, minimizing height above canopy), should be used.

Industry Training

The Railroad industry, state Departments of Transportation, commerc ial applicators and other entities responsible for applying ve getation management herbicides typically receive in-depth and frequent training re garding herbicide app lications - including information on reducing any possible off-target movement of applied herbicide. As an example, Progress Solutions, LLC, a leadi ng applicator in vegetation management servicing many electric companies, requires tr aining for new hires a nd annual training for all applicators. 10 Included in the training (attachment 1), is a module entitled “Drift Management” that includes instructions on choosing appropriate no zzle size, height of release spray, sprayer pressure and use of drif t retardants to limit any possible off-target movement. Similar training is also conduc ted by Departments of Transportation. According to Charles Flowers of the Arkansas State Highway and Transportation Department (AHTD), all certification, recertif ication and training of applicator personnel

8 Re-evaluation Decision Document: Dicamba; http://www.hc-sc.gc.ca/cps-spc/pubs/pest/_decisions/ rvd2008-28/index-eng.php

9 Re-evaluation Decision: Picloram; http://www.hc -sc.gc.ca/cps-spc/pubs/pest/_decisions/rvd2009- 02/index-eng.php

10 Email from Lee Atkins, Progressive Solutions, to Doug Wood, DuPont, dated June 24, 2010.

11is conducted by the Pesticide Coordinator fo r the University of Arkansas Cooperative

Extension Service. 11 In house training is also conduc ted periodically, utilizing expertise and training materials provided by basic ma nufacturers and supp liers of vegetation management products. Drift reduction and appl ication technology rela tive to off-target movement of pesticides is addressed in each training session. Although general use pesticides are used by the Depa rtment, all AHTD applicators are required to be certified in the Rights-of-Way category. The Depart ment utilizes weather instruments for documentation of environmental conditions, and us es drift control agents in all broadcast applications. Similarly, Alabama’s Depart ment of Transportation conducts annual training which addresses off- target movement - including drift, volatility, runoff and ground water considerations. In addition, th e Alabama DOT has issued “A Manual For Roadside Vegetation Management” (see attachme nt 2). According to Howard Peavey of the Alabama DOT, applicators are required to us e a drift retardant in all applications and

the DOT has set restrictions relative to wind speed and applications to sensitive areas.

The members of the National Railroad Contr actors Association (NRCA), who represents applicators of herbicides to the US Railroa ds, attend annual training conducted by Purdue University’s Department of Forestry and Na tural Resources, which includes certification and offers continuing education topics. Spray drift and off-target movement of herbicides are an integral part of the certification and training.

Application Technology

Typical application scenarios for aminocycl opyrachlor end-use produc ts include railroad application, utility rights-of-way s and roadsides. Control of unwanted vegetation in these areas is extremely important to provide safe ty to workers and the public, and to properly and efficiently maintain elec trical, railroad and highway sy stems throughout the United States. Application technology us ed in these types of applic ations has been designed to reduce the possibility of off-target movement . (Refer to Attachment 3 for photographs of typical spray equipment)

Railroad applications:

The majority of railroad applications are made using "hi-rail" truck sp rayers that actually

have railroad wheels and ride on the tracks. These range from 500 - 3,000 gallon capacity and can spray from 24 - 100 foot wide patter ns (12 - 50 feet from center of rail on both sides of the track). Routine railbed is spra yed 24 feet wide, while the 100 foot width is typical for railroad crossings where public safety is most crucial.

Railroad contractors are generally equipped with low drift, large capacity spray systems, utilizing 25 - 40 gallons/acre spray volumes a nd nozzles which deliver 1 - 10 gallons of spray per minute. This configuration equates to droplet sizes in the range of >500 micron VMD, and in many cases > 1,000 micron VMD.

11 Email from Charles Flowers, AHTD Facilities Manage ment, Arkansas State Highway and Transportation Department, to Doug Wood, DuPont, dated June 30, 2010

12Railroad contractors also tend to use drift control agents as part of the spray mixture,

which can result in a dramatic increase in droplet size depending on the specific product utilized. Specific nozzles used in railroad applications are "boomless" types such as boom busters, OC's (off center nozzles), XP boomjet, wobblers, solid streams, and radiarc's. Fixed nozzles used include floodjets, flat fans, 1/4 MEG low-angle flat fans, and

OC's.

Electric Utilities applications:

Applications made to Electric Utilities fac ilities and rights-of-way are primarily for brush control for general vegetation management. Th e range of application equipment includes backpack sprayers for applicators on foot in electric utility right- of-ways, ATV mounted sprayers using boomless configurations with either XP boomjets or boom buster nozzles, skidders (rugged vehicle for cl earing forest) using configurat ions similar to ATVs, and helicopter spray systems util izing some of the most i nnovative spray booms on the market to apply sprays exactly where they are required (for example, Thru-valve booms with a >800 micron VMD).

These applications will be of lower spray vol ume in some cases for efficiency (backpack 5 - 20 gallons/acre) or higher in other cases - for example with helicopters (5 - 30 gallons/acre). Backpack sprays can utilize "Constant Flow Va lves" to maintain a steady droplet size at a low pressure, minimizing spra y drift potential. In all scenarios, the spray nozzles will be large orifice/low pressure - producing coarse sp ray droplets, at a minimum, which allows the spray to be placed where intended. Placement is made easier with larger droplets since they are affected far less by any wind or vehicle movement.

Roadside applications:

Roadside applications are typically made us ing medium sized trucks, with tank sizes of 500 - 2,000 gallons spray, from the shoulder of roads utilizing low-drift nozzle technology. Spray systems include Norstar nuta ting heads that use so lid stream nozzles and oscillation to break up the streams into ve ry large droplets, or boomless nozzles such as the boom-buster or XP boomjets, which agai n result in large droplet size spectrums.

In summary, the vegetation management indus try has pioneered the development of low to no drift nozzle technology over the last thr ee decades to enable applications in close proximity to the public. The use of this technology, in combina tion with electronic controls and GPS, allows for rapid and consis tent placement of herbicide applications - thereby reducing the risk of off-target movement.

Adoption of Newer Chemistry

Requiring buffers for aminocyclopyrachlor end- use products will result in some land use managers continuing to use older, less effi cacious, more problematic products that do not currently have specified buffers - th ereby limiting the adoption of the new

13aminocyclopyrachlor technology. Other active i ngredients currently used in vegetation management products that either have less stringent buffer requirements, or no buffer requirements at all, include aminopyralid, picloram, triclopyr a nd clopyralid. These active ingredients are not scheduled for re gistration review until 2014, which means that any proposed buffer language resulting from these reviews would likely not appear on relevant end-use product labels until 2016 or later. This would seriously impact the adoption of aminocyclopyrachlor end-use produ cts if the current buffer proposals were

retained for this new active ingredient.

According to Tom Evans, a retired DuP ont vegetation management manager with extensive experience in railroad and hi ghway applications, assigning buffers to aminocyclopyrachlor end-use products would en courage applicators to continue to use products that otherwise require DOT HAZMA T placarding (such as Diuron), products designated as known carcinogens, products that are highly volatile (such as dicamba), products with known groundwater issues (such as picloram), and pr oducts containing 2,4- D (which is considered highly toxic if absorbed through skin). In addition, Mr. Evans

notes that the continued use of these products would greatly in crease the pesticide load in the environment versus the adoption of lower use rate aminocyclopyrachlor end-use products. 12

Control of Economically Important Weed Species

As BEAD concluded in its review of th e Public Interest Finding statement for aminocyclopyrachlor, this new act ive ingredient demonstrates be tter long term control of Leafy Spurge (Euphorbia esula) than any currently registered herbicide product. In addition to Leafy Spurge, aminocyclopyrachlor is effective on a number of other invasive and noxious weed species that are not being optimally controlled by currently registered products. Attachment 4 illustrates the broad spectrum of control of aminocyclopyrachlor versus currently registered competitive products.

Of particular note is rece nt efficacy work conducted with aminocyclopyrachlor on Cogongrass ( Imperata cylindrica ), an important new invasive weed of concern in southern and southeastern states. Over $8 million in federal monies was appropriated for the states of Alabama and Mississippi to ai d in the control/eradi cation of cogongrass in 2009. Of the currently registered products, gl yphosate and imazapyr are very effective at controlling cogongrass - when a pplied at the correct rates and timing. However, these products also kill the desirable grasses that gr ow in the same locations as the cogongrass, resulting in erosion problems and the further burden to re-establish the desirable grasses. During this bareground roadside period following application of non-selective herbicides, many other unwanted weeds and grasses of ten invade the area causing secondary problems in the planting and esta blishment of desira ble perennial grasses. An important attribute of aminocyclopyrachlor is the cont rol of cogongrass without severely harming the desirable grasses. Data from Au burn University demonstrates that aminocyclopyrachlor controls cogongrass in ba hiagrass roadsides in southern Alabama – with acceptable levels of phytotoxicity to es tablished grasses as compared to glyphosate

12 Email from Thomas Evans, consultant, to Dominic Watson, DuPont, dated July 9, 2010

14or imazapyr. Aminocyclopyrachlor offers an important new tool to help eradicate cogongrass in the southern and southeastern United States without causing permanent injury to desirable grasses. The ability to use aminocyclopyrachlor end-use products to control this, and other increas ingly problematic weeds, would be severely limited if the currently proposed buffers are included on the product labels.

Proposed Label Language

DuPont understands and supports the Agency’s e ffort to minimize any potential off-target movement of aminocyclopyrachlor containi ng end-use products which, in turn, will mitigate possible effects on non-target plant species. As an al ternative to EPA’s suggested buffers to non-target terrestrial a nd aquatic areas, DuPont is proposing label language, similar to that found on current vegetation management products, for the relevant Aminocyclopyrachlor end-use products. DuPont be lieves that this language,

combined with other recommended restrictions , will provide adequate margins of safety to terrestrial and semi-aquatic plan ts for Aminocyclopyrachlor uses.

Use Restrictions:

Do not make applications wh en circumstances favor movement from treatment site.

Do not apply or otherwise permit DuPontTM (product name)

, or sprays containing (product name)

, to come into contact with any broadl eaf crop or other desirable broadleaf plants.

Do not contaminate water intended for irrigati on. To avoid injury to crops and other desirable plants, do not treat or allow spray drift or run-off to fall onto banks or bottoms of irrigation ditches, ei ther dry or containing wa ter, or other channels that carry water that may be used for irrigation purposes. Do not apply to s now covered or frozen ground.

Avoid Injurious Spray Drift

Applications should be made onl y when there is little or no h azard from spray drift. Very small quantities of spray, which may not be visible, may seriously injury susceptible plants. Do not spray when wind is blowing toward susceptible crops, or other desirable plants, near enough to the appl ication site to be injured.

Aerial Application

Current Agency Proposal: “When applying by air, maintain a 50-foot buffer around non-target aquatic areas and between the point of direct application and the closest downwind edge of non-target terrestrial areas . Apply only using nozzles which will deliver coarse or greater (VMD >350 microns) droplets as defined by ASABE S572 standard. Do not release spray at a height gr eater than 10 feet abo ve the ground or crop canopy unless a greater height is required for aircraft safety. Do not apply when

15wind speed is greater than 10 mph. Do not apply during a temperature

inversion.”

DuPont Proposal: “When applying by air, apply only using nozzl es which will deliver coarse or greater (VMD >350 microns) droplets as defined by ASABE S572 standard. Do not release spray at a height greater than 10 feet a bove the ground or canopy unless a greater height is required for aircraft safety. Do not appl y when wind speed is greater than 10 mph. Do not apply during a temperature inversion.”

For aerial applications near susceptible crops or other desirable plants, use a drift control additive as recommended by the manufacturer

, or apply through a Micro-Foil or ThruValve boom

, or use an equivalent drift control sy stem. Thickened sprays prepared by using high viscosity invert systems or other dr ift control systems may be utilized if drift control is comparable to that obtained with drift control additives or the Thru-Valve boom. If a spray thickening agent is use d, follow all recommendations and precautions on the product label. Do not use a thickeni ng agent with the Micro-foil boom or other systems that cannot accommodate thick sprays.

Ground Application Restriction

Current Agency Proposal: “When applying by ground, maintain a 50-foot buffer around non-target aquatic areas and between the point of direct application and the closest downwind edge of non-target terrestrial areas. Apply only using nozzles which will deliver coarse or greater (VMD >350 microns) droplets as defined by ASABE S572 standard. Do not apply with a nozzle height grea ter than 4 feet above the ground or crop canopy. Do not apply when wind speed is greater than 10 mph. Do not apply during a temperature inversion.”

DuPont Proposal: “When applying by ground, apply only using nozzl es which will deliver coarse or greater (VMD >350 microns) droplets as defined by AS ABE S572 standard. Do not apply with a nozzle height greater than 4 feet above the ground or canopy unless necessitated by the application equipment. Apply with the spray boom or nozzle height as low as possible. Do not apply when wind speed is greater than 10 mph. Do not apply during a temperature

inversion.”

For ground applications, spray drift can be re duced by keeping the spray boom as low as possible by applying 20 gallons or more of spray per acre; by using spray pressures no greater than are required to obtain adequate plant covera ge; by using large-droplet producing nozzle tips; by usi ng drift control additives; by using shielded-sprayers or other drift control systems; and/or by spraying when wind velocity is low.

16Conclusion

DuPont believes that the Agency proposed buffers to non-target aquatic areas and nontarget terrestrial areas are not necessary to mitigate off-target movement of aminocyclopyrachlor end-use products used in vegetation management programs. Requiring such buffers will likely result in drastically reduced adoption of this new technology in Vegetation Management programs.

At the same time, DuPont understands and s upports the Agency’s effort to minimize any potential off-target movement of aminocyclopyrachlor containing end-use products which, in turn, will mitigate possible effects on non-target plant species. DuPont believes that this can be accomplished through the best management practices that are currently in place in the vegetation management industry. Therefore, as an alternative to EPA’s suggested buffers to non-target terrestrial a nd aquatic areas, DuPont is proposing label language, similar to that found on current vegetation management products, for the relevant Aminocyclopyrachlor end-use products. DuPont be lieves that this language,

combined with other recommended restrictions , will provide adequate margins of safety to terrestrial and semi-aquatic plan ts for Aminocyclopyrachlor uses.

1718 Attachments

1) Drift Management training module for Progressive Solutions, LLC. 2) Excerpt on Spray Drift Management from “A Manual For Roadside Vegetation Management” (Alabama Department of Transportation). 3) Examples of typical Herbicide A pplication Equipment for Vegetation Management 4) Efficacy comparison of Aminocyclopyr achlor and Competitive Products on Noxious and Invasive Weed Species

# Attachment 1

Drift Management training module for Progressive Solutions, LLCProgressive SolutionsAccording to the Environmental ProtectionAgency (EPA), 500 million pounds of pesticidesare applied annually in the United States. It isestimated that 3% of this total will drift.That’s equal to 3000 tractor trailersfull of chemical in the wrong place!Drift is defined as the off-target movement ofpesticides through the air at the time ofapplication.Pesticide drift can cause several problems frompesticide exposure to nearby workers, residentsand animals, to damage to susceptible crops.Drift will also reduce the amount of chemicalthat is available to control the intended pestand may render an application inadequate.Since the chemical and the application costmoney, drift not only is environmentallywrong, but it is also a costly and inefficient wayof doing business.Drift cannot be totally eliminated duringpesticide application because of technologyconstraints, but there are ways to minimizedrift to levels approaching zeroDrift can occur in all forms of pesticideapplication:High VolumeLow Volume backpackRoadside truckIn general, drift can be influenced by factors inone of these four categories:Spray characteristicsWeatherApplication equipment and setupOperator skillThe overwhelming factor influencing drift isdroplet size. As a general rule of thumb, smalldroplets do not have enough mass to drop fast,so they remain airborne and exposed to airmovement longer than larger droplets.The height of release of spray will influencehow much droplets will travel downwind. Thismay not be as critical for ground sprayers, butit is very important for high volumeapplication.No “shooting from the hip”with backpacksprayersHigh Volume Applicators should not spray toofar from the ground, generally no higher 8-12feet during the application. Any additionaldistance will give droplets an opportunity to beinfluenced by wind and be deposited off target.When using hydraulic nozzles, higherpressures will produce more fine droplets andincrease the drift potential of an application.Pressure has been demonstrated to not be aneffective way to increase coverage and canopypenetration.Drift retardants are usually added to the spraymixture in order to increase the viscosity of thespray solution. Increasing the viscosity of thespray will reduce the number of small droplets.Although drift retardants are a tool to be usedto decrease drift potential, their contribution islimited. You should manage nozzle type,height and operating pressure correctly tominimize drift potential. Do not rely solely ondrift retardants.Wind speed is the most important factorinfluencing drift. High wind speeds will movedroplets downwind and deposit them offtarget. Generally, pesticide application shouldbe avoided if wind speed is greater than 10mph. The most effective way to check windspeed is to use a wind meter.Wind direction will influence where off-targetspray droplets will be deposited. A carefuloperator will try to apply pesticides wheneverthe wind is blowing away from sensitive areas.High air temperature and low relativehumidity go hand-in-hand in creating a worstcase scenario for pesticide drift. Under theseconditions, spray droplets can evaporate veryfast and become more susceptible to windforces. Air temperature can also influenceatmospheric stability and off-target movementof spray droplets.Evaporation will reduce the size of the dropletsreleased in the spray. For typical applications withground applicators, droplets of 50 microns and lesswill completely evaporate to a residual core ofpesticide before reaching the target. Droplets greaterthan 200 microns will have no significant reductionin size before deposition on the target. Evaporationof droplets between 50 and 200 μm is significantlyaffected by temperature, humidity and otherweather conditions. Some pesticide formulations aremore volatile than others. For example, 2,4 D orMCPA esters are susceptible to vapor drift, while2,4-D or MCPA amines are practically non-volatile.Under a given spray situation, any one of thepreviously mentioned factors may be the mostcritical in reducing drift hazards. Ultimately, itis the applicator’s job to determine the criticalfactor and to take precautions against it. Byexercising good judgment regarding bothequipment and weather factors relative to eachapplication, applicators can minimize driftpotential in nearly every case.Drift is undesirable for economic,environmental and safety reasons. Efficientapplicators don't spend money for pesticides towatch them drift away from their target fields.Chemicals are potent and require preciseapplication. Unsatisfactory coverage couldresult if a significant portion of the chemical islost in drift. This could require re-spraying thesame area. We could be sued in court if spraydrift damages sensitive crops in a farmer’sfield.The environmental effects of spray drift areequally costly and unacceptable. By reducingdrift to a minimum, we can reduce thepotential for pollution of streams, lakes andother water supplies that could endanger fishand wildlife.Regardless of how accurately an application ismade, the possibility of drift is always present.You can minimize this possibility by selectingthe right equipment and using sound judgmentwhen applying pesticides. Your judgment canmean the difference between an efficient,economical application or one that results indrift, damaging non-target crops and creatingenvironmental pollution.

# Attachment 2

Excerpt on Spray Drift Management from “A Manual For Roadside Vegetation Management” (Alabama Department of Transportation)Veg. Mgt. Man. Chapt. III 19 SPRAY DRIFT CONTROL

Physical drift can be defined as the move ment of spray particles or droplets

away from the spray site before they r each the target plant. Ground inversion can

prevent the settling of very small droplet s and allow their movem ent away from the

spray site during calm conditions. The amount of drift depends upon (1) the size of

the droplets, (2) weather conditions and wi nd speed, (3) target location/distance and

(4) the height above the ground that the spray is released.

Droplet size is determined by the desi gn of the nozzle, or ifice or opening size

and pump pressure. In general, low pressu res and large orifice sizes tend to

produce large droplets, whereas high pr essures and smaller orifice sizes will

produce small droplets. Tar get setback and height above ground that the spray is

released become important since they dete rmine the time required for droplets to

reach the ground.

Weather factors include wind speed, te mperature and humidity. Wind speed

and direction principally determine the dire ction and movement of the spray droplet

after release from the nozzle. Temperat ure and humidity can a ffect the rate of

droplet evaporation. As the diameter of a drop decreas es, the ratio of surface area

(many smaller droplets) to volume increases and evaporation occurs at a faster rate.

The time of exposure to evaporation conditi ons also increases with smaller droplet

size. The potential amount of physical dri ft varies with the met hod of application.

There is a large difference of risk bet ween hand tank, ground and aerial spraying.

The hazards from off-target drift depend on (1 ) nature of the hazard, such as water,

plant species, growth state, etc.; (2) legal pesticide tolerances in crops; (3) distance

from the application site, (4) wind direction and air stability; (5) type, form and rate of

the herbicide; and (6) the mix carrier (water, fertilizer or oil). Herbicides require

certain coverage or drops per unit area of leaf surface for effective control.

Spray droplets evaporate more slowly in (wetter) 70% relative humidity and

faster in lower (drier) relative humidity. Droplets falling thr ough dry air decrease in

size and are subject to drift and possible chemical trespass.

To reduce the possibility of chemical trespass, a drift control agent is

frequently added to a spray tank in an attemp t to minimize spray drift to adjacent

sensitive areas.

Drift control products, such as Nalcot rol®, Ground Zero®, Control®, Valid®,

Sta-Put®, and numerous other s, usually contain some percentage of polyvinylVeg. Mgt. Man. Chapt. III 20 polymers or acrylic copolymers. When added to a spray tank, a drift control agent

hydrates in the spray solution resulting in larger spray droplets and fewer fine

droplets.

There are several inherent problem s associated with the use of these

products. Some of these products c an only be used with water soluble or

emulsifiable pesticides. This means t hey shouldn't be used wit h wettable powders,

dry flowables, water dispersible granules, flowables, aqueous suspensions, or liquid

suspensions. Operators must read the drift control agent label carefully to determine

if there is such a prohibition.

The use rate varies with the particula r product used, the spray pressure and

the type of spray tips used. Usually the rate is given in a range of fluid ounces per

100 gallons of spray mix. An operator should, init ially add the lowest rate

recommended. Increase the rate as needed. A thickened or "stringy" spray mix

indicates that too much drift control agent was added. Only the manufacturer of the

agent knows if it is possible to "unthicken" a spray mix. This mistake can cause loss

of time, equipment, possibly pesticides, and money. Operators must read the label

and use the lowest labeled rate.

There is no standard mixing order among the different drift control agents.

The proper mixing order discuss ed earlier is still correct for mixing different products

of different formulations together. Howeve r, operators will have to read the label and

determine the proper time to add the drift control agent in relation to the other

formulated products. In general, products that require agitation to remain in

suspension are added to the tank first and agitated well before the addition of any

other product. If an operator mixes his pestici des in the wrong order or adds the drift

control agent at the wrong time, he may end up with a "mayonnai se-like" mixture

that can't be sprayed.

Wind conditions are obvious to the applic ator and strict procedures must be
followed. Spraying must stop anytime the spray solution cannot be maintained
within the target area. ALDOT policy is to stop when wind velocity reaches 8 - 10

mph. Often times the crew can treat the downwind side of highways and return later

to treat the opposite side when wind conditions are more favorable. Following are a

number of field observations that spray operators may use to alert them to wind

speed changes. Hand-held wind gauges can verify observations.Veg. Mgt. Man. Chapt. III 21 Field Observations Wind Speed (mph)

Chimney smoke rises up, air motionless 0

Chimney smoke drifts slowly, air rises 1 - 3

Leaves quietly rustle, flags stir 4 - 7

Leaves and twigs move 8 - 12

Branches move and flags flap 13 - 18

Small trees sway and flags ripple 19 - 24

Large branches move and flags beat 25 - 30

Whole trees move and flags extend 31 - 38

Twigs break and walking is difficult 39 - 46

PERSONAL SAFETY

Toxicity is not the only factor that determines how dangerous a chemical is to

humans or animals. Anyone who handles pesticides should also be concerned with

the hazard of the chemical. The terms toxicity and hazard do not mean the same

things. Toxicity is the capacity of a subs tance to produce injury or death. Hazard

includes two factors: toxicity and exposure. It is defined as the possibility that injury

will result from the use of a substance in a given formulation, quantity, or manner.

Some hazards do not include toxicity to humans or other animals. For

example, sulfur, oils, and m any other chemicals are considered safe or relatively

safe to animals, but may pose considerable haz ards to some plants (phytotoxicity).

A pesticide may be extremely toxic but present little hazard to the applicator

or others when used:

 In a very dilute formulation.

 In a formulation that is not read ily absorbed through the skin or readily

inhaled.

 Only occasionally and under conditions to which humans are not exposed.

 Only by experienced applicators t hat are properly equipped to handle the

chemical safely

# Attachment 3

Examples of typical Herbicide Application Equipment for Vegetation ManagementVegetation ManagementSprayer & Nozzle Types2010Thru-Valve Boom (TVB)Waldrum Specialties is acompany formed by “Tex”Waldrum over 30 years ago,and has been a steadysupplier of innovative lowdrift technology for sprayersin the VegetationManagement market.Helicopter ApplicationsRight-of-Way ApplicationsExamples of spray equipment used in right-of-way spraying include ATV’s, andhandguns using rollover valves and CFV’s.ATV’s use “boomless” nozzles due tothe heavy brush, while the handguns operate from backpack sprayers targetingspecific species of brush. Helicopters are also used in this market.Railroad ApplicationsRailroad applications usetrain-powered sprayers formainline treatments, butextensively use spray trucks,like the one shown, to sprayrail yards and all other raillines. Highly sophisticatedapplication systems.Roadside ApplicationsRoadside spraying is done almost exclusively with “Boomless”sprayers, like the ones shown below, which allow for projection from theroad out to the target. The boomless spray nozzles or systems use verycoarse droplet sizes to enable precise placement of spray whererequired. Nozzles like those shown inherently produce larger dropletsdue to their sheer size, dictated by the spray width and forward speed.

# Attachment 4

Efficacy comparison of Aminocyclopyrachlor and Competitive

Products on Noxious and Invasive Weed SpeciesMAT28 Comparison on Noxiousweeds•Comparison of data from labels, Noxious weed list fromWestern States, Data from summary charts of replicatedfield trials were used for Aminocyclopyrachlor,–Picloram comparison was 8 oz ai/A–Aminopyralid comparison was 1.75 oz ai/A–Data on perennial weeds was taken at 200 to 365days after application•Labeled claims of suppression or control at seedling orearly stages were rated yellow•Aminocyclopyrachlor (MAT28)EH 9-09MAT28AminopyralidDicambaPicloram2,4-DGlyphosateYellowStarthistleStarthistleDiffuse KnapweedDiffuse KnapweedRussian KnapweedSpotted KnapweedSpotted KnapweedKochiaLeafy SpurgeLeafy SpurgeCanada ThistleCanada ThistleMusk ThistleMusk ThistleField BindweedField BindweedPoison HemlockPoison HemlockNoxious Weeds Control ComparisonNoxious Weeds Control Comparison80 to 100%50 to 70%>50 or not labeledMAT28AminopyralidDicambaPicloram2,4-DglyphosateMesquiteMesquiteNewer weed species tobe added to labelKudzuCogongrassCogongrassGorseScotch broomRushskeletonweedskeletonweedWild carrotWild carrotCompetitive ProductsCompetitive Products–Noxious speciesNoxious species80-100% control51-70%< 50% or not labeled