UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OCT 11 2012 \ 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registration Review: Trifloxysulfuron-sodium 

(119009) 

FROM: 

THRU: 

Biological 

Sunil Ratnayake, 

Analysis 

Biologist 

Branch (__ 

~..... '"<..A ~ ~ ~ · 

Sepehr 

Science 

Haddad, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist t{ ~ 

Stephen Smearman, Economist 

Economic Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Arnet Jones, Chief ;;J ~-) YY~...-u:...-t:Y" Biological Analysis Branch ~ 'l 

Diann Sims, Chief 

Science Information and Analysis Branch 

Timothy Kiely, Chief ~- .. '· ~ 

Biological 

Economic Analysis 

and Economic 

Brartch 

Analysts 

~ J 

Division 

_ ~ 

(7503P) 

TO: Kelly Ballard, Ch~mical Review Manager 

Risk Management and Implementation Branch 1 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: October 3, 2012 

INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management roles of pesticides that are beginning to undergo registration review. The 

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

oftrifloxysulfuron-sodium and eventually the general public. This document builds upon the 
data provided in the "Usage and Label Use Data Packages" that are also provided to Registration 

Review teams by BEAD. The document is based on information and data available to BEAD as 

of September 26, 2012 

Trifloxysulfuron-sodium was first registered in the United States in 2003. This herbicide 

belongs to the sulfonylurea family and it inhibits the activity of acetolactate synthase enzyme 

which is important for the synthesis of branched chain amino acids (leucine, isoleucine, and 

valine). Trifloxysulfuron-sodium is applied as a tank mixed treatment on fallow seedbeds in the 

fall and as a post-emergence treatment or post-directed application to control or suppress a 

broad spectrum of weeds including, annual and perennial broadleaf weeds, grasses, and sedges 

in agricultural and non-agricultural sites described below. Similar to other sulfonylurea 

herbicides, trifloxysulfuron-sodium has a greater activity at very low rates than many other 

herbicides and it is rapidly absorbed through the leaves and roots of susceptible weed species 

COMMON FORMULATIONS AND APPLICATION METHODS 

Trifloxysulfuron-sodium is formulated as granular, water dispersible granules and emulsifiable 

concentrate. 1bis herbicide is applied using ground application equipment and according to the 

label instructions chemigation and aerial applications are prohibited (Envoke®, Product Label, 

2011). 

USE SITES 

Agricultural Use Sites 

Trifloxysulfuron-sodium agricultural use sites include citrus, almonds, tomatoes, cotton, and 

sugarcane. 

Non-agricultural Use Sites 

Trifloxysulfuron-sodium non-agricultural use sites include ornamental turf for lawns, golf 

courses, cemeteries, athletic fields, and ornamental turf grown for sod. 

USAGE 

Agricultural Usage 

Trifloxysulfuron-sodium was registered in 2003. Based on private market usage data from 2004-

2011, usage averaged approximately 5,000 pounds active ingredient (a.i.) for 670,000 acres 

treated. The average a.i. rate over this time period was 0.007 pounds a.i./acre. More recently, in 

2011 the average a.i. rate was at a high of0.009 pounds a.i./acre. Figure 1 presents 

trifloxysulfuron-sodium usage in pounds a.i. over the 2004-2011 timeframe. Figure 2 presents 

total area treated in acres over the 2004-2011 tim~frame. (Proprietary Data, 2004-2011). Both 

figures show a sharp increase (almost a doubling in use) between 2010 and 2011. 

2 
FIGURE 1. Triflox sulfuron-sodium Usa e in Pounds Active In redient (2004-2011) 

10,000 -,----------------------

2004 2005 2006 2007 2008 2009 2010 2011 

Years 

Source: Proprietary Data, 2004-2011 

FIGURE 2. Triflo sulfuron-sodium Total Area Treated in Acres 2004-2011) 

1,200,000 

2004 2005 2006 2007 2008 2009 2010 2011 

Years 

Source: Proprietary Data, 2004-2011 

Figure 3 shows use of trifloxysulfuron on cotton and sugarcane. Between 2004 and 2011, 

approximately 70 percent of total use has been on cotton with the remaining 30 percent on 

sugarcane. Between 2010 and 2011 pounds a.i. applied more than doubled on cotton and 

sugarcane, while total area treated in acres for both crops also doubled. 

3 
FIGURE 3. Use of Trifloxysulfuron-sodium- Percent of Total Lbs. Applied on Cotton and 

Su arcane 2004-2011 

Source: Proprietary Data, 2004-2011 

FIGURE 4. States with Highest Use of Trifloxysulfuron-sodium- Percent of Total Lbs. 

A lied 2004-2011 

6% 

MISSISSIPPI 

7% 

8% 

10% 

Source: Proprietary Data, 2004-2011 

The states with the highest use in terms of percent of total pounds a.i. applied are Florida (27%) 

followed by North Carolina (14%), Georgia (13%), Louisiana (10%), Arkansas (8%), 

Mississippi (7%), and Texas (6%) as shown in Figure 4. The "other" states shown in Figure 4 

accounting for 15 percent oftotal use include Alabama, Tennessee, South Carolina, Missouri, 

California, Virginia, Kansas, and Oklahoma. Sugarcane is grown primarily in Florida and 

Louisiana. Its use on cotton is more widespread. Cotton is grown in Arkansas, Georgia. 

Louisiana, Mississippi, North Carolina, and Texas. 

4 
Agricultural Usage by Crop Reporting District 

Another measure of usage is the use intensity. In this analysis, the use intensity is expressed as 

the pounds a.i. applied per acre of land in farms. This differs from the application rate, which is 

expressed as the pounds a.i. applied per treated area. 

Figure 5 spatially represents trifloxysulfuron-sodium usage by crop reporting district for 2006-

2010. The area depicted in red on the map (in Louisiana), is due to the higher application rate of 

this active ingredient on sugarcane as opposed to cotton. 

FIGURE 5. Trifloxysulfuron-sodium Usage by Crop Reporting District (2006- 2010) 

Average Pounds Per 

1,000 Acres of Farmland 

- <0.02 

0.02-0.04 

D o.o5-o.o8 

0.09-0.27 

0.28-0.45 

This is a map of agricultUral 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 of counties (USDA, 2010). Pesticide usage is displayed as average pounds (for the years 2006-

201 0) per 1,000 acres of farmland 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 of agricultural land 

used for crops, pasture, or grazing. It also includes woodland and wasteland not 

5 
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 CREP 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 

land 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 of a farm or ranch. Land under the exclusive use of a 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 w_as reported in the name of the cooperative group that used 

the land. In many instances, an entire American Indian reservation was reported 

as one farm (2007 Census of Agriculture, USDA). 

Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2006-2010). 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 of pesticide 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 of farmland) 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 of the 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) of a crop or crops with a high application rate and frequency of application. 

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. 2006-2010. 

USDA, 2006-2010. NASS Crop Reporting Districts. 

USDA, 2007. Census of Agriculture. 

Non-Agricultural Usage 

In terms of non-agricultural usage, data are available only for golf courses for 2004 and 2006 and 

landscape for 2004 as shown in Table 1 below. It is important to note that this data is dated but is 

presented in this document for reference. 

Table 1. Trifloxysulfuron-sodium Select Non-Agricultural Usage (Pounds A.I.) (2004-2006) 

Site 2004 2006 

Golf Courses 450 125 

Landscape 30 NIA 

N/A=not available 

Source: Kline & Co., 2004, and 2006 

6 
BIOLOGICAL ASPECTS RELEVANT TO TRIFLOXYSULFURON-SODIUM 

Trifloxysulfuron-sodium is a sulfonylurea herbicide and the mode of action ofthis class ofherbicide 

is inhibition ofacetolactate synthase (ALS) enzyme. According to the Weed Science Society of 

America (WSSA) mode of action classification, this herbicide is included in the group ofB/2 

herbicide site of action. It was reported that 127 weed species have developed resistance to the 

herbicides with.this mode of action (Weedscience.org, 2012). Trifloxysulfuron-sodium is a 

systemic herbicide highly effective in controlling broad spectrum ofbroadleaf, sedges, and grass 

weeds at a very low rate compared to other herbicides and it is widely used to control or suppress 

troublesome weeds such as morning-glory (Ipomoea spp.), sicklepod (Cassia obtusifolia), hemp 

sesbania (Sesbania exaltata), pigweed (Amaranthus spp.), nutsedge (Cyperus species), barnyardgrass 

(Echinochloa crus-galli), and Johnsongrass (Sorghum halepense) in cotton, sugarcane, and tomato 

production (Envoke®, Product Label, 2011). Based on the usage information shown in Figure 2, the 

acreage treated with trifloxysulfuron has increased significantly from 2010 to 2011. The increase in 

number of pounds applied and the number of acres treated with this herbicide could be due to the 

spread of troublesome weeds such as glyphosate resistant Palmer amaranth found in cotton fields 

(Hollis, 20 12). 

HISTORY OF BEAD ASSESSMENTS FOR TRIFLOXYSULFURON-SODIUM 

A search of the BEAD Official Records data base and the Section 18 data base did not find any 

assessments or Section 18 requests specifically for trifloxysulfuron-sodium. 

INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON 

TRIFLOXYSULFURON-SODIUM 

Any available information on non-agricultural uses such as target pests, rates, and area treated 

would be useful. 

CONCLUSION 

Trifloxysulfuron-sodium's use on cotton and sugar cane significantly increased from 2010 to 

2011. It remains to be seen whether this was a one year fluctuation due to increased pest 

pressure, resistance or other environmental factors without future use data. It is clear that 

trifloxysulfuron-sodium has become a valuable tool for growers to control, morningglory, 

nutsedge, sicklepod, Johnsongrass, barnyardgrass, and Palmer amaranth species in cotton and 

sugarcane production. 

7 
REFERENCES 

Crop Management. 2012. Syngenta Develops Herbicide to Control Key Broadleaf, Weeds, 

Sedges, Grasses in Cotton, Sugarcane, Citrus, and Tomatoes. 

http://www.plantmanagementnetwork.org/pub/cm/news/envoke/. Accessed on September 14, 

2012. 

Envoke®, Product Label, 2011. Syngenta Crop Protection, LLC. Greensboro, North Carolina 27419. 

http://www.syngentacropprotection.com/pdf/labels/SCP1132AL 1 E 121 O.pdf. 

Accessed on September 6, 2012. 

Hollis, P. 2012. Glyphosate-resistant pigweed in a class all alone among cotton pests. Southeast 

Farm Press. http:/ /southeastfarmpress.com/cotton/ glyphosate-resistant-pigweed -class-all-aloneamong-cotton-pests-0. Accessed on September 13, 2012. 

Kline & Co., 2004, and 2006. 

Proprietary Data, 2004-2011. 

USDA, 2006-2010. NASS Crop Reporting Districts. Online: 

http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass. Accessed 

on September 6, 2012. 

USDA, 2007. Census of Agriculture. Online: 

http://www.agcensus.usda.gov/Publications/2007/index.asp . Accessed on September 7, 2012. 

Weedscience.org. 2012. Herbicide Resistant Weeds. 

http://www. weedscience.org/summary/MOASummary.asp 

Accessed on September 18, 2012. 

8