UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D

.C. 20460 

## JUN 2 4 2013

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### MEMORANDUM
SUBJECT:
FROM:

THRU:

TO: BEAD Chemical Profile (BCP) for Registration Review: Picloram Salts and Esters Case (005101, 005102, and 005104) Sunil Ratnayake, Biologist 

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# ~ Biological Analysis Branch \

## ''''-flf'""'~**~** Jihad Alsadek, Economist 

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# A-~ Science Information and Analysis Branch Stephen Smearman, Economist 

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### Economic Analysis Branch**~fA.t..V'J~vY'I.CY'** ' 

### Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Branch Diann Sims, Chief

# ,iCl/L.~~~.,.....**....u** Science Information and Analysis Branch Timothy Kiely, Chief

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# J Biological and Economic Analysis Division 503P) Christina Scheltema, Chemical Review Manager Risk Management and Implementation Branch 3 Pesticide Re-evaluation Division (7508P) 

### ProductReview Panel Date: March 20, 2013 INTRODUCTION The purpose ofthis document is to convey usage information and a broad overview ofthepest management roles ofpicloram. This document builds uponthe data already provided inthe usage and label use datapackages that are also provided to Registration Review teams by BEAD. The document is based on**inf~rmation** 

### and data available to BEAD as ofMarch 20,2013.

### Picloram was first registered 

### as a pesticide inthe U.S. in 1964 and the Registration Eligibility Decision was issued in 1995. This chemical belongs to the pyridine family ofherbicides and it is a restricted use pesticide (RUP). According to the WSSA (Weed Science Society ofAmerica) mechanism ofaction classificationpicloram is identified

### as a member ofthe group 4 herbicides. Picloram is a systemic herbicide used for control ofwoody plants and a wide range ofbroadleaf weeds inrange management programs. It

### can be applied 

### as a pre-or post emergence treatment. Picloram is a synthetic auxin and this type ofherbicides kills susceptible plants by mimicking the plant growth hormone auxin (indole acetic acid). Applications ofpicloram at effective rates, causes uncontrolled and disorganized plant growththat leadsto plant death (Tu et al., 2001). In general, picloram is more toxic to broadleafweeds than to grasses species. Picloram may be used with other herbicides such 

### as bromoxynil, diuron, 2, 4-D, MCPA, triclopyr, and atrazine to broadenthe weed control spectrum. Picloram is a restricted use chemical withlong-term residual effects. No more than one pound a.e. should be applied per growing season for right-ofway and in other non-ag. sites, and application should be made every two years in forest sites.


### IDSTORY OF BEAD ASSESSMENTS FORPICLORAM A search ofthe BEAD Official Records data base did not fmd any benefits assessments or Section 18s for picloram. 

### COMMON FORMULATIONS AND APPLICATION METHODS Picloram is formulated as emulsifiable, soluble concentrate, and 

### as a solution-ready-to-use. Picloram can be 

### applied by broadcast, spot treatment 

### as foliar (leaf), bare soil spray, 

### as a basal bark treatment, and/or by air 

### as broadcast spray.


### USE SITES Agricultural Use Sites Picloram is anherbicide registered for use onbarley, fallow, oats, wheat, pastureland, and in forestry. Non-Agricultural Use Sites Picloram is an herbicide registered for use on ornamentals, conservation reserve program land, non-agricultural sites, rights-of-way, industrial sites, storage yards, fencerows, industrial storage areas, and hedgerows. 

### USAGE Agricultural Usage The use trend for picloram decreases during the 1998-2011 timeframe. Ninety-eightpercent of the usage is onpastureland during this time period and decreased almost 50 percent during this time period, 

### as presented inFigure 1. The remaining 2 percent is used onbarley, fallow, and wheat.



### 2

### Fi ·cultural Usa e Datafor Picloram in Pounds A.I. on Pastureland 1998-2011)

PoundsA.i.

0 

# 8 N 

### g 

# g 8 N N N N Years Source: Proprietary Data, 1998 -2011**~** 0 N ...... 0 0 N**~** 0 N**~** 0 N 0

...... 0 N



### From 2007-2011, the annual total agricultural usage averaged approximately 810,000 pounds acid equivalent (a.e.) for 5.3 milliontreated acres with an overall application rate of0.2lbs. a.e. per acre, versus an overall application rate of0.1lb. a.e. for the long time period 1998-2011. On average, the states withthe most agricultural usage interms ofpounds a.e. applied are Texas (26%), Oklahoma (12%), and Arkansas (10%), and the top states in terms ofthe total area treated are Texas (31 %), same percentage for Oklahoma (12%), and Arkansas (9%). (Proprietary Data, 2007-2011). Table 1, for the same time frame (2007-2011), shows the crops withthe mostuse in terms of total pounds ofactive equivalent (a.e.) applied, and percent oftotal acres treated
.



### Source: Proprietary Data, 2007-2011 AgriculturalUsage by 

### Crop Reporting Districts Another measure ofusage is the use intensity. Inthis analysis, the use intensity is expressed as the pounds a.i. applied per 1,000 acres ofland in farms. This differs from the application rate, 

### 3which is expressed as the pounds a.i. applied pertreated area. The average application rate for the period 2007-2011 is 0.2 lb. a.i. per acre. As shown in figure 2 the highest use intensity is 240 lbs. per 1,000 acres ofland in farms. Figure 2 spatiallyrepresents picloramusage by crop reporting district for 2007-2010. The areas depicted inred onthe map in Western Louisiana andNorthern Arkansas is the pastureland areas. Non-Agricultural Usage Recent non-agricultural data are not available for this chemical; the most recent is for 2006.
BIOLOGICAL ASPECTS RELEVANT TO PICLORAM Picloram is an herbicide used to control a variety ofannual and perennial broadleafweeds and woody species. Picloram is readily absorbed byplantroots, foliage, and it is readily translocated throughout plants. Itcanpersist in an active form inthe soil from several months to years, and can also be released from the roots oftreated plants into the soil, where othernon-target species maytake it up and be injured orkilled (Hickman et al. 1990). Examples ofweeds successfully controlled using picloram include: leafy spurge 

### (Euphorbia esula), knapweeds 

### (Centaurea spp.), horsenettle 

### (Solanum carolinense), milkweed 

### (Asclepias L.), field bindweed 

### (Convolvulus arvensis), and Russianthistle 

### (Sa/sola kali) (Picloram K Specimen Label, 2013). Ithas been reported that yellow starthistle 

### (Centaurea solstitialis) has developed resistance to picloram. In addition, presence ofwild mustard 

### (Sinapis arvensis) biotypes resistantto picloram has beenreported in Manitoba, Canadathathad beentreated withherbicides with the mechanism ofaction similar to picloram (dicamba, MCPA, and mecoprop). Also, biotypes ofcarpet burweed 

### (So/iva sessilis), a dicot, have developed resistance to clopyralid, picloram, and triclopyr 

### in the NewZealand (International Survey ofHerbicide Resistant Weeds, 2013).
DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON PICLORAM Additional information, interms ofpounds a.i. applied, average application rate, regional application, time ofapplication, number ofapplications peryear onnon-agricultural sites, such as ornamentals, rights-of-way, industrial sites, from theregistrant would improve future assessments ofthis chemical. REFERENCES Alligare, Picloram K Specimen label. Alligare, LLC, 2013. http://www.alligarellc.com/ products/PDFs/PICLORAM K LABEL.pdf Accessed on March 11, 2013. EPA. 1996. Re-registration Eligibility Decisionhttp://www.epa.gov/oppsrrdl!REDs/0096.pdf
. Accessed onFeb. 11, 2013.
4

### Extoxnet. 2013
. http://extoxnet.orst.edu/pips/picloram.htm
. Access date. Feb. 12, 2013. Hickman, M. V., Messersmith, C. G., and R. 

### G. Lym. 1990. Picloramrelease from leafy spurge roots. 

### J. Range Manage. 43(5):442-445. International Survey ofHerbicide Resistant Weeds. 2013. http://www.weedscience.org/summary/MOASummary.asp Accessed on Feb. 25, 2013
. Proprietary Data, 1998

-2011 Sabba, R. 

### P, Ray, I. 

### M., Lownds, N., and T. M. Sterling. 2003. Inheritance ofresistance to clopyralid and picloram inyellow starthistle (Centaurea so/stitialis L.) 

### is controlled by a single nuclear recessive gene. http://www.ncbi.nlm.nih.gov/pubmed/14691320. Accessed onMarch 12, 2013. USDA, 2007. Census ofAgriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp. Accessed on March 13, 2013. USDA, 2007-201

### l. NASS Crop Reporting Districts. Online: http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass
. Accessed onMarch 14,2013.

5

### Appendix Figure 2. Picloram Use Intensity by 

### Crop Reporting District (2007-2011)

Average Pounds Per 1,000Acres of Farmland 

# -<1

2-4 

## 0 5-7 8-13

- 14-24 This is a map ofagricultural pesticide usage at the Crop Reporting District (CRD) level prepared by BEAD for use in the Environmental Fate and Effects Division documents. These maps are used to help visualize where the pesticide being considered is most likely to be used and can be helpful in scenario selection and placing the exposure assessment in context. CRDs are boundaries created by USDA NASS which are aggregates ofcounties. Pesticide usage is displayed as average pounds (for the years 2007-2011) per 1,000 acres offarmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007)
. Farmland or "land in farms" is defined as follows: The acreage designated as "land in farms" consists primarily ofagricultural land used for crops, pasture, or grazing. It also includes woodland and wasteland not actually under cultivation or used for pasture or grazing, provided it was part of the farm operator's total operation
. Large acreages of woodland or wasteland held for nonagricultural purposes were deleted from individual reports during the edit process. Land in farms includes CRP, WRP, FWP, and CREP1 acres. Land in farms is an operating unit concept and includes land owned and operated as well as land rented from others. Land used rent free was reported as
1 CRP: Conservation Reserve Program; WRP: Wetland Reserve Program; FWP: Farmable Wetlands Program; CREP: Conservation Reserve Enhancement Program 

### 6land rented from others. All grazing land, except land used under government permits on a per-head basis, was included as "land in farms" provided it was part ofa farm or ranch. Land under the exclusive use ofa grazing association was reported by the grazing association and included as land in farms. All land in American Indian reservations used for growing crops, grazing livestock, or the potential of grazing livestock was included as land in farms. Land in reservations not reported by reservation, individual American Indians or nonNative Americans was reported in the name ofthe cooperative group that used the land. In many instances, an entire American Indian reservation was reported as one farm (USDA, 2007). Usage is based on private market surveys ofpesticide use in agriculture (Proprietary Data, 2007-2011)
. The survey data are limited to the states that represent the top 80-90% of acreage for the individual crops; therefore, use may be occurring in regions outside the scope of the survey. CRDs showing no usage of pesticides may be due to either the lack ofpesticide use in the region or non-participation in the agricultural surveys. In addition, across the years, there may be variations in the specific crops included in the CRD survey. This may result in a lower annual average for the CRD. This map displays ratio data (i.e., average pounds per 1,000 acres offarmland) summarized at a very highlevel. Readers are strongly cautioned against trying to over interpret the map without examination of the underlying data. The underlying data may explain some ofthe many reasons that a Crop Reporting District may have
.a high value for a particular active ingredient such as significant acreage (compared with the CRD as a whole) ofa crop or crops with a high application rate and frequency ofapplication. The reader should pay particular attention to the figure legends and realize that a map prepared for a particular chemical is not directly comparable to a map prepared for a different chemical. Scale and units of measurement do matter and may be different between maps. Sources: Proprietary Data. 2007-2011. USDA, 2007. Census ofAgriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp
.



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