UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 

## DEC 01 2011

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### SUBJECT: BEAD Chemical Profile for Registration Review: Trifluralin (036101)
FROM: Bill Phillips, II, PhD, Agronomist

# .-dJId~ BiologicalAnalysis Branch 

# <I3{tT
.**~** Jihad Alsadek, PhD, Economist

# ~ If:- -J1 Science Information and Analysis Branch AndrewLee, PhD, Economist

# /l~ C

# ~ Economic Analysis Branch 

# V'" Biological and Economic Analysis Divisi (7503P) THRU: Arnet Jones, Chief

# ~**1'21~** Biological Analysis Branch

## ~"'j Diann Sims, Chief 

# Lla...,
.........**.e...~,.,-.L-'** Science Information and Analysis Branch Timothy Kiely, Chief Economic Analysis Branch 

# <11- ltv\.

# ~ Biological and Economic Analysis Division (7503P) TO: Kelly Ballard, Chemical Review Manager Risk Management and Implementation Branch 1 Pesticide Re-evaluation Division (7508P) 

### Product Review Panel date: October 12, 2011
INTRODUCTION The purpose ofthis document is to convey usage information and a broad overview ofthe pest management roles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status oftrifluralin, and eventually the general public. This document
. builds uponthe data already 1provided inthe "Usage and Label Use Data Packages" that are also providedto Registration Reviewteams by BEAD. The document is based on infonnation and data available to BEAD as ofSeptember 2011. Trifluralin is applied as a pre-plant incorporated andpreemergence herbicide used to control small-seeded broadleafweeds and some grasses in agronomic, horticultural (ornamental and vegetable), and industrial sites. In addition, applications can**b~** made through chemigation. The herbicide trifluralin is a dinitroaniline (DNA) withthe mechanism ofaction ofinhibiting the microtubule proteintubulin whichresults inthe disruption ofcellular mitosis. Weed control is achieved through root uptake ofemerging seedlings. This chemical is classified as a group 3 herbicide bythe Weed Science Society ofAmerica.


### USE SITES Agricultural Uses Small fruits, Grapes, Strawberries, Citrus fruits, Nut crops, Pome Fruits, Stone Fruits, Tropical and Sub-tropical fruits, Beverage crops, Flavoring and Spice crops, Fruiting vegetables, Leafy and Stem vegetables, Root crop vegetables, Seed and Pod vegetables, Asparagus, Onions (Green), Fibercrops, Forage grasses, Forage legumes and othernon-grass forage crops, Grain crops, Sugar crops, Cotton, Crops grown for oil, Soybean, Forest Trees, and Uncultivated Agricultural Areas. 

### NOli-agricultural Uses Ornamental lawns and

### turf, Golfcourse turf, Ornamental herbaceous and woody, Around agricultural structures, Uncultivated Non-Agricultural Areas, Commercial, Industrial and Institutional areas, Rights-of-ways, Pre-paved areas, fencerows, Septic areas. There is a combination ofmore than 1,000 agricultural and**no~-agricultural** use sites registered for this herbicide. Overall, the agricultural uses oftrifluralin are wide ranging and account for the majority ofthe herbicide applied inthe U.S. Approximately 98% ofthe use sites include agronomic andhorticultural crops (field and container), as well as turffanns. Based on total acreage treated and the total amount applied the primary use oftrifluralin is in cotton and soybeanproduction (Figures 1 & 2). The non-agricultural use sites labeled for trifluralin include conservation reserve areas, fence rows, golfcourses, industrial areas, landfills, landscape plantings, residential areas, rights-ofway, turf(lawn care and institutional), and other less common areas such as pathways, pre-paved areas, septic drain fields, sidewalks, tennis courts and underground cables.


### COMMON FORMULATIONS AND APPLICATION METHODS Trifluralin is fonnulated as wettable powder, impregnated materials, water dispersible granules, and soluble and emulsifiable concentrate. . 2Application methods for this herbicide include aerial and ground application (banded, broadcast and spot spray, broadcast and hand-held granular, soil incorporated, and chemigation). '


### USAGE Agricultural Use and Usage Data Based onprivate marketpesticide usage data from 2006-2010, the annual total agricultural usage averaged approximately six million pounds active ingredient for seven milliontreated acres for an overall application rate ofless than 1 lb. a.i. per acre. From 2006-2010, the crops with the mostuse in terms oftotal pounds ofactive ingredient applied are cotton (53%), soybeans (25%), and alfalfa (5%). The crops withmosttotal area treated (TAT) are cotton (54%), soybeans (24%), dry beans (4%), and tomatoes (4%). On average, the states withthe most agricultural usage interms ofpounds a.i. applied are Texas (45%), Iowa (11%), California (9%), Georgia (6%), and Minnesota (4%). (Proprietary Data, 2006-2010). 

### Agricultural Use Trends Figure 1provides usage trends as pounds applied for the largest agricultural markets for trifluralin. The use oftrifluralinon alfalfa, cotton, soybeans, sunflowers and other crops declined during the period 1998-2010.



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### Fi e 1. Trifluralin A 1998-2010 12,000,000



### o 1998199920002001200220032004200520062007200820092010 Years "-Alfalfa

___Cotton
-'- Soybeans**Sunflowers**

_ Other

Other crops include dry beans/peas (3% each), spring wheat and tomatoes (2% each), and sugarcane, canola, fallow, and green beans (1 % each). Source: Proprietary Data, 1998-2010 

### Figure 2 provides usage data for 2006-2010. The use oftrifluralin on alfalfa declined during this time period. Use on cotton and soybeans fluctuated, declining between 2006 and 2008 and increasing between 2009 and 2010. The use on other crops**w~** 

### relatively stable.
Fi e 2. Trifluralin A 4,000,000


## :i III "-Alfalfa '0 c

# ~* ___Cotton ;:, 0 

# ..**~** 

# * 

# • -.-Soybeans 

### )E H H )( )(**Other** 0 2006 2007 2008 2009 2010 Years Other crops include dry beans/peas and tomatoes (3% each), sunflowers and sugarcane (2% each), and fallow and green beans (1% each). Source: Proprietary Data, 2006-2010



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### Non-Agricultural Use and Usage Data The use oftrifluralin on golfcourses declined from 31,000 lbs. a.i. in 2002 to 4,000 lbs. a.i. in 2006. The use oftrifluralin by landscape contractors declined between 2002 and 2006 from 50,000 lbs. a.i. in 2002 to 24,000 lbs. a.i. in 2006
. The use ofthis chemical by lawn care operators (LCOs) fluctuated between 2002 and 2006. The use oftrifluralin in institutional 

### turf facilities rose from 32,000 lbs. a.i. in 2002 to 401,000 lbs. a.i. in 2006. The use oftrifluralinrose also on

### turfmanagement and horticultural nurseries from 311,000 lbs. a.i. in 2002 to 532,000 lbs. a.i. in 2006. Because there are a limited number ofpreemergentherbicides available for use by homeowners and professionals alike, formulations oftrifluralinfor use in landscape and lawn sites have high benefits. Trifluralin can be formulated as a granular as well as a fertilizer impregnated form making it very simple for homeowners and landscapers to apply to lawns and to incorporate and/or coverbeneath mulch in landscape beds. Consumers used about 400,000 pounds oftrifluralin in 2003 andjustunder one millionpounds
. in 2005 (mostrecent data available to EPA). In 2003 the use oftrifluralinby retail consumers, based on lbs. a.i., was as an herbicide/fertilizer mix, while in 2005 the primary uses oftrifluralin was divided equally between garden and lawn care fertilizer mix applications. More than 400,000 lbs. a.i. was applied in 2005 while use as a fertilizer mix was 500,000 lbs. a.i. Ofthe DNAherbicides that overlap inthese use sites, pendimethalinwas the primary herbicide for lawn care use (>3.0 million lbs. a.i.), while benefin (800,000 lbs. a.i.) use was only slightly higher than**trfl~alin** (500,000 lbs. a.i.). However, neitherpendimethalinnorbenefin were ranked within the top 98% ofthe herbicides used for garden weed control. While trifluralin is notthe only preemergence herbicide labeled for garden use, the use sites ar€?numerous (flowerbeds, vegetable, undertrees and shrubs) and the pest spectrum for these uses is atthe same time broad. The total amount oftrifluralin active ingredient (a.i.) applied by consumers are nowhere nearthe level ofthe agricultural uses; however, the benefits are nonetheless significant and thus are not well represented by the totallbs. a.i. reported.
. T bl 1 T'fl al' N A' ltural U

a e nur 10 on- .gncu se 2002 2003 2004 2005 2006 Segment/Site (lbs. a.i.) (lbs. a.i.) (lbs. a.i.) (lbs. a.i.) (lbs. a.i.) GolfCourses 31,000 

## - 23,000 

## - 4,000 Landscape Contractors 50,000 

## - 46,000 

### - 24,000 Lawn Care Operators (LCOs) 127,000


## - 171,000


## - 65,000 Institutional TurfFacilities 32,000 

# - 43,000 

## - 401,000 TurfManagement & 311,000 

### - 306,000 

### - 532,000 Horticultural Nurseries Consumers 

## - 400,000· 

## - 970000·· 

# - , - = Data are not available for the use within the year. 

### • Lawn as a fertilizer mix product. 

### ••470,000 lbs. a.i
. in garden (flowerbeds, vegetable, under trees and shrubs) & 500,000 lbs. a.i
. in lawn as a fertilizer mix product. 

### 5

### Source: Kline and Company, Inc., 2002-2006


### BIOLOGICAL ASPECTS RELEVANT TO TRIFLURALIN Only goosegrass 

### (Eleusine indica) has been confirmed as resistant to trifluralin in the U.S. This weed species is not a noxious weed, however it maybe important with respect to crop yield loss in regional areas. ' Because trifluralin is highly lipophilic it is quickly taken up byplants. Itis also this lipophilicity that limits its movementthrough plants by binding with cell structures such as membranes. It is for this reason that this herbicide only controls germinating seedlings by causing roots to stop growing before they are able to beginto supportplant growth. The advantage ofcontrolling weed species at this stage ofgrowth eliminates the chances ofweeds competing for resources priorto their control as well as their producing seed.


### HISTORY OF BEAD ASSESSMENTS FORTRIFLURALIN In 2009, BEADprepared a usage report which included trifluralin as one ofthe chemicals being evaluated in support ofa red legged frog endangered species assessment for California (Carter and Kaul, 2009). This information may be useful inthe reexamination ofrisk-benefit balance for trifluralin, which is the purpose ofregistration review process.


### DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ONTRIFLURALIN Obtaining additional information onthe following items would improve future BEAD assessments ofthe importance ofTrifluralin and may be required as part ofthe registration review ofthis pesticide. Information is needed inthe following areas regarding specific uses where trifluralin may have significantbenefits: 1. Golfcourses, 2. Landscape contractors, 3. Lawn care operators, 4. Institutional turffacilities, 5. Turfmanagement companies, 6. Horticultural nurseries, and 7. homeowner uses. 

### REFERENCES: Proprietary Data, 1998-2010 Kline and Company, Inc., 2002-2006 Carter, J. and M. Kaul. 2009. County-Level Usage for Strychnidin; Strychnine; Tric1opyr, butoxyethyl ester; Tric1opyr, triethylamine salt; Diflubenzuron; Trifluralin ;Thiobencarb; Chlorpyrifos; Vinclozolin; Iprodione in California in Support ofa Red Legged Frog Endangered Species Assessment. June 8, 2009.
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