UNITED STATES ENVIRONMENTAL PROTECT ION AGENCY WAS HINGTON , D . C . 2 0460



### DEC 0 3 2 0 10

OFFICE OF CHEMICAL SAFETY "OJ" Dn., I rr", ..... .,t\n:;..". ....... 

### MEMORAND UM S U BJE CT : FROM:

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TO: B EAD C hemica l Profile fo r Re gi s tration R e view : T e rb acil (0 1270 1 ) S unil Ra tnayak e, B iologist .• . 0 B iol ogical An alysis Braoc h IW""" \ Sepe hr H addad, E n viro nmen tal P rotection Spee ialist 

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# J Scie n ce In f ormati on and An aly s i s Bran ch 

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# I J E c o n o m ic An aly si s Branch

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# ues-« Bio l ogical An a l ysis B ranch D iann S ims , C hief

# j{];,0'-""-.,~**"1""'/** S c ience Inform ation and Analy sis Branch Timoth y Kiel y, C h i ef ' AI I 

# A Economic Analy s i s Br anch 

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# r \ Bi o logica l a nd Econo mic Anal ysis i vi s ion (75 OJJ) Jam es Parker , C hemical Review Mana ge r Pe s ticide Reeva luation D ivi s ion (7508?) Peer Review Panel date : 0812512010 

### I NTROD U CTIO N The p urpose o f th i s d ocumen t i s t o convey u s age inf orma ti on and a bro ad o verv i ew o f th e pe st mana gement ro le s of pe s tic ide s th at are be ginnin g t o u ndergo registrati on re view . The antici pated aud ience c onsi sts o f th e team o f E PA s ta fT currentl y eva luat ing the regi stration sta tus o f T erbaci l, and e ventually the genera l pub lic. Thi s d ocum ent bu ilds upon th e d ata alre ady p rovided in th e "Usag e an d Labe l Us e Data Packa ge s " th at are a l so p rov id ed t o Regi strati o n Re view team s b y B EA D . Te rbacil i s a se l ectiv e herbicide used t o co ntr o l b roadleaf w eed s o n terre s tri a l f ood/fe ed crop s .Terb ac il i s f orm ul ated a s w ate r d i sper sible g ranu les a n d w ettab le po wde r . T he se pr odu ct s c an be a pplied b y ai rc ra ft o r gro und e quipme nt i n cluding bo om sp rayer s. U se p rac tic e l i m itat io n s in clude p ro hi bition of ap plica tio n s throu gh a n y ty pe of irri ga tion sy s tem . G raz ing or f e eding fo rage or h ay f rom trea ted a reas to liv estoc k i s a l s o p ro hib ited (E PA . 199 8) . 

### It i s s prayed o n s oil s u rf a ces pre ferab ly ju s t befo re or d uri ng th e pe riod of a ctive wee d growth . T e rb aci l i s ab s orbed b y root s an d k ill s w eeds b y inhi bi t ing ph otosyn th esis a t p h otos y s tem I I. 

### It is a m em ber o f the sub st ituted ura c il c hem ica l fam i ly (Extoxne t , 1 996) . 

### USE S ITES Maj or u se s ites ofterbacil under the terre s trial fo od ca te gory are appl es, mint, s u garcan e, aspara gus, bla ckberry , boy senberry , d ewberry , loganberry . peac h. raspberry, yo u n gbe rry , and s trawberry . Alfalfa i s the maj o r u se s ite of terbacil u nder the terr e s tri a l feed cate g ory . I n a dd it io n. terbacil i s u sed for weed con tr o l in fore s try ( e.g, cotto nwood ) . 

### C O MMON F OR MULA TIO NS AND A PP LICA nO N MET HODS Thi s c he mical i s fo rmu lat ed as w ate r d i sper sible gran u le s a nd w ettab le powd er . Te rbac i l m ay be a pplied by d irect s p ray wi th a boo m sp ray e r, as soi l b and t rea tme nt or as so il b roadcas t tr ea tment u sin g a boo m s p raye r or b y aeri al a pp lic ation . 

### U

SAG E A gricu l tu ral U sage Ba se d o n p rivate m arket pe s ticid e u sage d ata , th e an nu a l t o tal a gric ultura l u s a ge a veraged a pp roximately 6 4, 000 po und s ac ti ve ingredi ent (A .I. ) f or 8 6,0 00 ac res f rom 1 9 98 t o 20 08 (GtK K yn etec , 1 99 8 M 2 008 ). T he u s e o f terbacil s te adi ly d ecre a s ed f rom i t s pe ak in 1 9 9 8 th rough 20 02 a nd th en o nce a gain f rom a hi gh in 2 00 3 throu gh th e lo w e s t lev el in th e p ast 1 1 y ears in 2 008 (See F ig ur es 1 a nd 2).



### 2Figure 

### 1. T erbacil Usage, Pounds Applied, 1998 -2008

1998 1999 2000 2001 2002 2003 2004 2005 2006 200 7 2008 Y ear Figure 2. T erbacil A cres T reated, 1998-2008



### 1 60 , 000

u**~~** 

### 1 998 1 999 2 000 200 1 2 002 2003 2004 2 005 20 06 2 007 2 008 Year



### 3Fro m 1 998-2008 , the large s t marke t s in te rm s of t otal po u nds of active i n gr edient appli ed and ac res treated was for app le s (3 2%), a lfalfa ( 31% ), pea che s ( 1 8%), and s uga rcane ( 16 %). See F ig ure 3. 

### Fi gure 3. P oun ds A I Applied B y 

### C rop, 1998-2008

3%

1 8 %

31 % E! A pples • Alf alfa o Pea ches o S ugarcane • Oth er

T he s tates with th e m o s t agric u ltura l u sage in ter m s of p ou nds A I. applied ar e: O kl ahoma (2 3%), Wa shingto n (18%) and Loui s iana (17 %), fo llow ed b y N ew York, Mi ch igan , Geor gia, Ne w Jer sey, So uth C aroli na, Texa s and Penn syl vania each at less than 10 % (G fK Ky n e tec, 1 9 98- 2008) . T h ese s ta tes are a l so th e larg est in t enn s of tota l a c re s tr eated fr om 1998 -2008 . S ee F igure 4 . 

### F igure 4. State s with the Highes t Use-Percent 

### of To tal L bs Applie d, 1998 to 2008 .

4% 8 0 K lJ*l O MA • LOU ISIANA o WASHINGTO N D NEWYOR K • MICHIGAN • GEORGIA • N EW JERSEY o SOUTH CAA.OLl NA • TEXAS • PE NNSYLVANIA 18%

4

### N on -A gricultura l Usa ge B EAD reviewed a vai l able non -agricultura l s ources, bu t no i nf ormation was f ound o n th e u se of terbacil i n non- agricultural u se s ites. 

### F igure 5. Terbacil T op Crops U sage, 1998 ·2008

1 40 ,000 ' r- - - - - - - - - - - - - - - - - - - ---,



### o Alfa lfa o Peaches • Apples iii S u garcane

1 998 1999 2000 200 1 200 2 2003 200 4 2005 2 006 2007 2008 Y

ear 

### Ov er th e 19 98

- 2008 t ime p eriod , u sage o n s ugarcane h as d ecreased from a h i g h of m ore th an 50, 000 l b s AI to a lm ost none , whi le th e u se on a lfalfa has r emained f ai rl y co nstant thr ougho ut t he s ame ti me p eriod . T h is decrease of terbaci l u sage m ay be d u e var i ations in s ugarcane production d ue to th e heavy s ubsidizations o f o ther s ugar-producing cou ntries. In ad dition, d evelopment o f new s ugarcane var ieties with less to lerance t o te rbac il ma y h ave pl ayed an imp ortant ro le o n thi s decline in terbacil u sage . T he u se o n p eac h es decreased b y over 95 percent b etween 2 007 and 2 008. Whi le th e use o n cane berries wa s on ly a vai lable for 20 06 thro u g h 2 008 , a s ma ll amo unt o ft erbaci l use was o bserved in 20 08 on ly . 

### BIOLOGICAL ASPECTS RELEVANT TO T ERBACIL Vo la ti l ity , d eath o f non - target p la nt s d ue to th e herb icide dr ift , lo n ge r residua l act ivity are s o m e of th e prob lems of thi s h erbicide (Si nbar® Speci men La bel, 2 010). A dd i tionally, terbacil s hould n ot b e applied to areas w here th eir roots m ay ex tend or i n l o catio n s whe re th e c hemica l may b e was hed o r moved in to co ntact w ith th eir root s. When terb a ci l i s ap plied, mea s ures to pr event dri ft of d ry p owder or s pray to d esirable p l ants s hould b e a vo ided. Res idual ac tivity i s a prob lem w ith terbaci l and it co me s w ith th e two -year carryover restriction. C ro ps lik e co rn , oats, wh eat, a nd sq uash ma y be l ess se ns i tive to th is herbicide , b ut ph yt ot oxic effec t s on co llards h ave b een



### 5ob served ev en six mo nth s a fter the applica tion of this h erb i cide (So utheast Farml're ss, Feb ., 2009 ). 

### R esis tan ce Manageme nt Developm ent ofresistance in b iotypes of diffe rent weed s pecies has been reported . Velvetleaf 

### (Abu tilon theophru stit; s m oot h p igweed 

### (Amaranthus hybridus ), pal mer a marant h 

### (Amaranthus palme ri), po well amaran th 

### (Amaranthus 

## powettiv; red root p igweed 

### (Ama ranthus re trojlexus). ta ll waterhe mp , 

### (A maranthu s t ub er culatus (syn. r udis } , co mmon ragwee d 

### (A mbrosia ar temisiifolia) , a nd la mb squarters 

### (Chenopodium album) are t he m a j or we eds f ound to be re s i s tant to terbaci l ( WSSA,20 10) . Man agement of h erbicide re si stance i s ne cessary to d elay an d to a void th e proliferation o f resistant weed bi otypes. T illa ge , cro p ro tatio n, a nd u se o f tank m ix p artners and s e que n ti a l applicat io n s of herbic ide s with d iff erent m odes o f ac tion ar e important in thi s asp ect. HI S TO RY O F B EAD AS SE S SME NTS F O R T ERB A CIL Te rbaci l has n ot bee n th e s u bjec t o f an y ri sk m it igati on i mpact ass e ss ment s de veloped b y B EAD . However, there ha ve b een a few e mergency exe mp tion (Sec tion 18) req uests f ro m M ary l and, V irginia , Geo rgia. an d D e l aware ove r t he years that have bee n rev iewed by B EAD . In a ll ca ses th ese req uest s for terbacil were intended fo r u se o n wa termelon . A RED wa s co mpleted fo r Te rbacil i n 1998 . DATA NEEDS R ELEVANT T O B EAD'S F UTURE W ORK ON TE R BACI L Obtaining additi onal information on the f o llow ing item s w ould improve B EAD 's as se ssment of the importance of terbaci l as a herbicid e. Thi s as sessme nt i s l ikely to be re quired as pa rt of the regi s tration r eview of this pe s tic ide . I . Co mparative efficacy inf ormation of t erb ac il to s i milar produc t s re gi s te red fo r s i milar u s es f o r ap ple s, a lfalfa , and pe ache s. 2 . Inf ormation o n g ro w e r's s election cri ter ia f or growt h re gulator at eac h crop s tage whe re terba cil m ay be u s ed . 3. T erbaci l u sage d ata f or fore s tr y and terre stri a l feed s ite s and inform ation o n e ffec t ive a lternative s. 4 . Re aso n s fo r th e decline in terb aci l u sage on s ugar can e and p eaches . 5 . Worker ac tivi ties th at oc cur in tre a ted fi e lds a t th e t yp ical tim e of terbacil a pp l ications . 6 . Co mparativ e c os ts of terbaci l ve rs us o ther h erbicides i n i den tifi ed u s e s ites. R EF ERE NCES GfK Kynetec , 1998 -2 008 . Proprietary Data . Environmental Protection Age ncy (E PA ) . 2010 . Section 18 Act ion Da tab ase . Avai lable at : http ://cfpubl .epa.gov /oppre f /section 18 / searchre sult .cfm . Retri eved 8 /18/ 10 . Ext ox net. 2 010 . Te rbacil. Pe s ticide In format ion Pr ofile . http: //extoxnet.or st.edulpip slte rbacil.htm .

6EPA, 1998 . R . E . D . Fac t s. Terba cil . Publicat ion o f the E n v i ronmental Prot ection A gency http: ""'\\'W .epa .go v /opp srrd IIRED slfactsheet sl003 9fact. pd f Sinbar Specimen Label. 2 010 . Te s senderl o Ke rley , In c . P hoenix, AZ 8 5008, U S A. http : //"'\\'W.growercentra l .c o mlUPLOADSIPDFS / sinbar % 20label % 20(05 -07l .pd f R oberson . R. 20 09 . So uthEast FarmPre ss. http : //southea s tfannpre ss .com /vegetable stobacco /\'cgctab lcs -hcrbicide s -0210 1 WSS A , 2010 . Internatio na l Surve y of H erbicide Res istan t Wee ds . http : //ww,,,,, ' . weed scicnce .org !Summarv lUspec ic sMOA .asp ? lstMOA ID -=4&FmHRACGrou p=Go 

### Appe ndix 1: Emer gency Exemp tion R eques ts for Terbacil The EPA Sec tion 1 8 Act ion Database o nl y retrieves req ue s t s from 200 I o nward , a lthough oc cas io n a ll y o lder reque s t s a re availa ble . The f ollowin g BEA D as sessmen t f r om 1 994 w a s n ot i ncluded in th e datab ase : Al i, G h ul am; George Keitt . 1 9 94 . Rev iew of M ary land Reque sts f or E mergency Ex emption of C lomazone an d Terba c il f or Use on Watennel on t o Co ntro l Bro adle afWeed s ( DP# 2 02043 ; 2 02044) . Th ere w as al so a B EAD a nalysi s d one fo r the f oll owin g as s essment whi ch a lso w as n ot rec orded in the Section 18 Acti on d atabase . Z inn. N ico le ; And rew Lee . 2 003 . Rev iew o f a Reque s t f o r Eme r genc y Exe m ption o f T e r bacil in Ge orgia for Us e o n W ate nnelo n t o Co ntro l Annu a l Morn i ng G lory a nd Pal mer A maran th (D P # 313 717). 

### EPA S ection 18 Action's for Te rbacil DP BAR COD E(S) Site P est Applicant Received Response St atus FOR HEAD Date D at e A SSESSM E /'Ii TS, I E C ON DUCTE O WATERME LO N W EEDS DELAWAR E 1 19 / 1 9 97 5 18

/199 7 I SSU ED WAT ERMELON W EEDS MARYLA ND 1 1/ 15 / 19 96 5 / 8 1 1997 I SSUED 232026 . 232027 WA T ERMELO N W EEDS V IRGI N IA 1 1 / 18/ 199 6 51 8

/ 199 7 I SS U ED W

ATERMELON W EEDS V IR GIN IA 10 12 21 1997 11 124/199 7 I SS UED WA TERMEL ON WEEDS D ELAWA RE 112 7 11 998 2/6 / 1998 I SS UED WA TERMELON MORNING M AR YLAND 1 122/ 1 99 8 2/6 / 1998 I SS UED GLORY WATERMELON W EEDS D ELAWARE 3 116/ 1999 3 125 1 1999 ISSU ED WAT ERMELON MORNING MARYL AND 1 127/ 1999 312 5 /1999 I SSUED GLOR Y W ATE RMELON BR OADLEAF V IRG INIA 1 /8

/1 999 3 12 5 /1999 ISSUED W EEDS WATERMELO N W EEDS D ELAWAR E 2 /10 12 000 4 /3 120 00 ISSUED WATERMELO N W EEDS MARYLA ND 2 /10/20 00 4 /312 000 IS SUED 7W ATE RMELO N BR OADL EA F V IR G INIA 11 1 9 12 000 4 /312000 ISS UED W EEDS W AT ERMELO N W EEDS D ELAWA RE 3 / 1512 001 3 12 81200 1 I SSUED WAT ERMELO N W EEDS MA RYLA ND 21 512 00 1 3 /2 81200 1 I SSUED W ATERME LON B R OADL EAF VI RGINIA 1 131 /2 001 3 /2 8/2001 I SS UED WE ED S WATERME LON W EEDS DELA WAR E 1 /25 12002 3 12 712002 ISSUED W ATERME LO N W EE DS MARYLA N D 21 1512 002 4 / 4 120 02 ISSUED W AT ERM ELO N BR OADL EAF V IR G IN IA 2 1 13 /2 00 2 4 /4120 0 2 ISSUED 28 129 1 . 28 1289 W EED S WAT ERMEL ON BR OADL EAF V IRGI N I A 11 1312 003 2 / 4/200 3 I NC O MPL ETE - W E EDS O UTSTA N DI N G DA TA R

EQUESTED W ATERMELON B ROAD LEAF V I RG IN IA 3 / 1

2 120 03 4/1 12 0 0 3 I SSU ED W E ED S W ATERMELO N M O RN INGG LORY D ELAWAR E 4 13 12 0 0 3 4 12 812 003 I SS UED WAT E RM E LON M ORN ING M ARY LA N D 4 12/2 003 4 12 9/2003 I S S U ED GLO R Y WATERM ELON BR OAD LEAF F L OR IDA 1 2/3 12 003 3 /2212004 WIT HDRAWN W EEDS W ATE R.. \1E LON WEEDS D ELAWAR E 2/2 3/2 004 3 /26 /2004 IS SUED 2 80592 WAT ERMELON W EEDS MAR YLAND 2/24/2004 3 /2 6 /2004 I SS U E D WATERM ELO N W E ED S VIRGI NIA 3 / 15 12 004 3 /2 6 12 004 IS S UED WATER M ELON W EEDS D ELAWAR E 11 3 /2 00 5 3 / 1 112 005 I SSUED W ATERME LO N BROAD LEA F V IR G IN IA 11 1 9 12 005 3 / 11/2 005 IS SU E D W EE D S W ATERME LON BR OADLEAF MAR YLA N D 3 /

812 005 6/6 12 005 IS SU ED W E ED S WAT ERM ELON BR OADL EAF G EOR G I A 2 / 1

412 005 7 / 15 / 200 5 IS SUED W EEDS W ATERMEL ON M ORN ING G EO RGIA 1 / 3 112 006 3 / 912 006 I SS U ED G LO RY & PALM ER AMARA NT H W AT E RMEL O N ANNUA L VIR G INI A 3 / 112 006 4 /6 12 006 ISSUED BR OADL EAF W EEDS WAT ERMELON A NNUA L D ELAWAR E 3 / 1512006 4 !25 12006 IS S U ED BR OAD LEAF W EED S W ATERME LON ANNUAL MARYLA ND 3 / 1 7 /200 6 4 !25/2006 ISS UED BR O ADLEAF WEEDS Sou rce . EPA (2 010 ). B EAD O ffiC ia l Re co rd s.



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