UN ITED S TATES EN VIRON MENTAL PROTECTION AGE NCY WASHI NGTON , D . C. 2 0 460 

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11 OFFICEOF CHEMICAL SAF ETY A ND POLLUTIO N P REVENTION M EMO RAND UM SU B JECT : B EAD C h e mica l Pr ofile f or Regis tration v iew : T hifen s ulfuron ( 128845)



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T O : Kylie Roth well, C hemical Review Ma nager R i s k M anage ment and Irnp le:nentation B ran c h 3 Pe sticid e Reevaluation D ivi s: o n (7508 P) 

### Peer R evi ew Pa nel d at e: August 25, 2010 I NTR ODUC TI O N Th e p urpose ofthi s d ocument i s to c onvey us age inf ormation a nd a br oad ove rview o f th e p e st man agement rol es o f pe s ticides that are b eg i nning to und er go re gi str ati on r eview . The an ticipate d audience co n s i sts o f th e te am o f E PA s taff c urrently ev aluating the regi st ration s tatuso f'thife ns ulfu ron - merhy l ", and eve ntua lly the ge nera l p ublic . Thi s docume nt bui ld s upo n the d ata a lready provided in the " Usage and Label Us e Dat a Packages" that a re a lso provided to Re gistration Review te ams by BEAD . Thifen su lfur on i s an herbicide u sed in s mall gr a in ( b a rley, flax , o ats, sa fflower, tritical e, and whe at) and s oybean crop s f o r the co ntrol o f s m a ll-s eeded broad leafweed s. Th i s che mical i s in th e f amily o f s u lfony l urea (SU ) . Th e He rbicide Re si stance Ac tion Co m m ittee and Weed Sc ience Soc iety o f Ame ri ca c lass ify thi s h erbi ci de in g roup 8. '2 2 • T he mode of ac ti o n i s v ia th e inh ibition of th e plan t e nzyme aceto lactate s y n th ase (ALS) . C urrently , there are s ev e ra l w eed s pecies r esistant to he rbicide s i n thi s f amil y , in c l uding thifensu lfur o n . 

### USE SITE S' Bel ow are the un ique ag ricultural a nd n on-agri cultur al u s e site s f or th ifen sul furon . A gricu ltural U se S ite s : Ag ri cu ltural f allow 

### I id le land 

### I co n servat ion re s erv e , b ar l ey, c ano la\rape, com ( un specified), c om - field , oat s, ri ce, s afflowe r ( u ns pe cifie d ), so rghum, soy beans ( unspecified) , s ugar beet, tr iticale, whe at

' Non-Agrcultural Us e Site s : C otton ( unspecified), flax


### CO MMON F O RMULAT IONS AND AP P LICATI ON METHOD S Th is c hemical is form ulated as dry flowable . 

### USAGE A gricu ltura l U se S ite s B ased on pri vate m arket pe st icide u s age da ta, the ag ricu ltural u s age ave raged a lmost 1 00 , 000 po und s ac tive i ngredient (A . I. ) f or abo ut 1 0 mill ion a c res f rom 1 998-2008 ( GfK Kynetec , 1998

- 2008 ) . Th e use o f thifensulfuron, i n t ot al pound s A . L per year, ove r the 1 998 -2008 year s p an, h as bee n relat ively c onstant wi th a s ligh t in c re ase i n 20 08.

I 3-( a-m eth oxy-e-methyl- I ,3 ,S -triazin-2

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- 2-ca rboxylie ac id 2 H erbicide Re s i stant Act ion Co mmittee http: // www. w ee dscie nc e.o r gls umm ary /Che mFa m i1 y S u m .asp? l s tActive=4 7 8 &btn S ub J '"' Go & I stHRA 

## c 3 I Th is is a summ ary o f me u sc sue s . Please refer to me PRD A ppend ix A : F ood 'Feed & N on-Food/Non-Fccd u ses C on s id e re d in Reg i stratio n R eview Wo rk P la nn in g f or a com prebcnsive li s t


### 2140 ,000 

### From 1 998-2008 , th e large st market s in te rms of total 

### pound s o f a ctive ingr edient appli ed are : wint er whe at ( 51 % ) , spring wheat (29 % ) , barle y (7 %), soybean s (7% ) , an d co m (5% ) . ( OlK K

ynetec , 1998-2008 ) 

### F

rom 1998- 2008, th e largest m arket s i n terms of total 

### area treat ed are : winter wheat (39%) , spring wh eat ( 27 % ), and s oyb ea ns ( 20 %). ( OlK Kynetec , 1 998-2008) 

### Th e state s with the most agricultur al usage i n t erm s of pound s A I applied a re : N orth Dak ota (2 0 %) , S o uth D akota (7 % ) , Washin gton (7 %) , Kentucky (7 % ) , and lllin ois ( 6.5 % ). 

### Th e st a

tes with th e highe st tot al ar ea treate d are : N ort h Dakota ( 18% ), South Dak ota (7% ), Wa s hington (7%) , Illinois (7%), and M innes ota . ( OlK K ynete c, 1998-2008) US E T RENDS 

### The f ollo wing g raph pro vides us a

ge tr end s, in term s o f p ound s 

### appli ed, for thifen sulfur on' s 

### l arge st a gri cultural mark ets . T he data in this se ction ar e pr ovided for preliminary s coping purpo se s . U sag e ha s been s teady with an i n cre ase in 20 08 prim aril y in s pring wheat and co rn .

1998 19 99 2000 2 001 2002 200 3 2004 2005 2006 2007 2008 Yea r 

### j 0 Barley

_ C orn 0 Wheat, Spr:n g 0 Wheat , Winter

_ All Other C rops 

### I N ote: "A ll Other Cr o ps" r ef

er

s to Cott on, Dry B ean slP eas , Fallo w, P a sture /Rang e, 

### R ice , Sorghum (Milo) , S oy beans , Sunfl ower s, and S weet Co rn . 

### 3

### BIOLOGI C AL A SPE CT S RELEVA NT TO T HE C H E:\II CAL TIIIF ENS ULF URON

METHYL I n o rder t o bro aden t h e s pec trum of thi s h erbicid e. t hi.e n su lfuron i s p rimari ly s o l d i n premi xed 

### prod uct s o r i s u sed as a tank 

### mi x partne r with o ther he rbi cides . Wee d s resistant to o ther h e rbicid e s in th is c hemica l fa m ily are a lso re sist ant t o thi fensulf ur o n . Re si sta nt we ed s inclu de 

### s pe c i e s s uc h as t all wa terhemp 

### (A maranthus tuber cu l a/us) an d wi ld m u star d 

### (Sinap is a rvensis f, HISTO RY OF B EAD ASSESS MENT S F OR CHEM ICAL T HIFENS ULF U RON

ME TH YL A s e a rc h of B EAD 's d o cum ent d ata b ases i ncluding BE AD's O ffici a l Rec o rd s an d the B EAD 

### S ecti o n 1 8 da ta ba se d id n o t re ve al an y reque st s , a ss essmen ts or r eview s f or th e u se o f th i f e n sulf uron -m e th y l b y che m ic al or prod uc t n ame (Ha rm o ny) 

### D ATA NEEDS R EL EVA NT T O B EAD' S F UT URE W O RK ON CHEMI C AL T HIFE NSUL FURON

- ME T II YL B EAD nee d s i nf orm a ti on for the ag ricu ltural u s e o ft hif e ns ulfuro n . Specifi cally, with regard s t o th e agro nomic u se s , wh at wee ds thifen sul furon i s u sed to co ntrol , w h a t are th e p ri mary c hemical a lterna t ive s thifen su l furon i s u sed t o con trol and w hat tar get s pec ie s h ave de mon s tra ted re s is tan ce . I n add it ion, econo mic d ata n e ed s fo r fu ture w ork in clu de the fo llo wi ng a gronom ic inf o rm a tio n: growe r s co st of th if e nsu l furo n i n terms cf co s t pe r po u n d A I an d th e c o s t pe r acr e tr ea tm ent , th e c ost o f a lternative c o ntrol s in term s o f th e c ost p er po u nd A I and the cos t per ac re tre at ment ; the p er c ent o f the part icular crop tr e a ted w ith thifen s ulfur o n ; p rodu c ti on dat a fo r fl a x, s a ffl o w er , o ats a nd tr iticale i ncl u ding p roducti on c osts f o r eac h o n a p er ac re ba s i s. 

### REFE RENC ES G fK K y netec , 1 9 9 8 -2008 P roprietary data . H e ap, 

### I. Th e In ternatio n al S urv ey o f H erbi c id e Re s i s tan t Wee d s . 2 010

4 H e ap , I. Th e I nternat io na l Survey o f Herb icide Resi s tant W e ed s . O n line . I nternet. Aug ust 12, 2010 . Ava ila ble w ww . weed s cience . c o m

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