UNITED STATES ENVIRONMENTAL PROTECTION AGENCY W ASHINGTON , D ,C, 20460 

## DEC 02 20 10

OF fiCE OF CHE MICAL SAFETY A ND POLLUTIO N PREV ENTION 

### MEMORANDUM SUB JECT: FROM:

T H R U:

TO: B EAD C hemical P rofile f or Reg istration Re view : C hlor i muron-ethyl ( 128901) 

### Sunil R atnayake, Bio logist /\ t 

### 0 Bi ological An aly s is B ranch 

# l

_ _**(\~~** Kath erine S tebbins, B iologist

## ~~ \ Scie nce Inf orm ation and A nalysis B ranch Jo hn Faulkner , Eco nomist

## (L~M 

# c--r

_ . . fh A/I /1/\ E conomic Ana lysis Br anch

### "~I 

# ::JTAJ.AA'(/YW, B iological a nd Ec o n o mic A nalysis D ivisio n (75 03P) A rnet Jo nes , C hief

# 1~ Bi ological An alysis B ranch

# L~ 

# . 

# U rT imothy Ki ely , C hief 

# 9l V E conomic A nalysis Bran ch \;,-- 

### B iological and Economic Analyst D ivision.5 0 P) 

### 1 

## J
. D iann S ims, C hief 

### Science Information and A nalysis Br anch W ilhelmena Liv ingston, C hemical Review M anager Pes ticide Reev aluat ion D ivision (75 08P) 

### Peer Review Pa nel date: May 1 9 ,2 010 

### IN TRODUCTION T he purp ose o f thi s do cum ent i s t o co nvey u sage information and a br oad overv iew o f th e pes t mana gement roles o f pe s ticide s th at are b e ginnin g to un dergo re gi str ation rev iew
. Th e anti cipated a udience fo r thi s paper co nsists of th e team of E PA sta ff c urrently e valuating the registration s tatus o f C hlorimuron-ethyl and eve ntually th e g eneral p ub l ic
. T his d ocument build s upon th e data a lready pr ovided i n th e " Usage and Lab el U se D ata Pa ckages " th at are a lso p ro vided to Registration Review teams b y B EAD.C hlorimuron- e th y l b elon gs to th e s ulfonylurea cla ss o f herbicid e that inhib its th e en zyme ac eto lactate s y ntha se ( ALS)
. It i s r egi stered for u se on s oybeans, field com , p eanut s and nonc rop are a s s uch as f encerows and road sides. C h lorimuron- e thy l c ontrol s gra s ses and broadleaf weed s. In g eneral, f or a s eason-long control o f gra s ses and broadl eaf w eed s , 1- 3 o z/acre planned s e qu e ntia l appli cation i s need ed
. For a gricultural u sage , s oybean i s th e predom inant us e s ite
. C hlorimuron-ethyl may be appli ed to soy bean crop at pre- plant, pre -em ergence , p o st
- emerg ence, or po stharv e st s tage s a s a band treatm ent , broad ca st , gr ound s pray , low vo lume s pray, or s oi l inc orporated treatment . T he pre -harve st int erval s a re 60 day s for so ybeans and 45 da ys for peanut s . C hl o rimuron-ethy l ma y al so be appli ed to n on -crop land at the foliar s tage a s a broad ca st tr eatment. U SE S I TES Agri cultural Us e Si tes C hlo rimuron- e th y l i s labe led f or u s e on s oy b e ans , p eanu ts , and fi eld c orn . T here i s a l so a s pecial lo ca l need s ( SLN) regi strati on f or c ranberries (W A). No n-Agricultura l Us e S ite s C h lo rimuron-ethy l ma y be applied to n on -crop a reas s uch a s: f encer ow s, r oad side s , e quipment s torag e ar e as, and o ther s imilar areas . COMMON FORM ULATIONS A ND AP PL ICATION ME TH OD S ' The onl y labeled f ormu lation i s dry flowable
. A ccording t o the label s, thi s A I ma y b e appli ed w ith a e rial o r gr ound equipm ent. T he type o f appli cation s i nclude : broadcast , band , so il in c orporated , lo w v o l ume , burn-do wn , and con servati on tillage treatm ents. T he type o f equipment that ma y be u sed include s: ground, aircraft , s prayer ( including bo om and band s prayers), low p re ss ure / low v olume s pra ye r s, and s oi l incorporation equ ipment. I This is a summary o f the app lication m ethods. P l eas e refer to th e P RD Appe ndix A: F ood/Fe ed & Non-Food/Non -Feed Uses Co ns id ered in Reg istr atio n R eview Work P lanning fOT a comprehensiv e list US AG E A gricu l tura l Usa ge Based o n pri va te mark et re search d ata fr om 1998

- 2008, th e annual agr icultural u s age av e rag ed a pproximately 9 0 , 000 p ound s f or n early 6 milli on a cres (G fK K ynetec , 1 9 98- 2 008 ) . The pr ed ominant m arket i s f or s oy bean s, which a ccount s f or 99 % of th e to tal pound s appli ed ( GfK Kynetec , 1 9 98- 2 0 0 8)
. ( Figure 1 ) F igur e 1 . C hlorimuron-ethy l Us age o n Ag ricultura l S ites



### 2Pound s AI Ap pli9d

• Soybeans
• l'eanlJls Cc> ""

So urce : O fK K y netec , 1 998

- 2008 

### The s tates w ith th e most a gri cultural u sage i n tenu s of p ound s A I applied are Illin oi s, O hio , Indiana , M isso uri , a nd Iowa. (F igure 2) These state s w ere als o th e top in tenu s o f t he t otal acre s tre ated. F igure 2
. Top S tates for C hl orim ur on- e thyl Us age o n Ag ricultural S ite s P ound s AI A pplied



## " '''''''' 

# , ,. So urce : G fK K ynetec , 1 998-2008 

### No n-Agricultural Us age U sage d ata is n ot available for the non -crop si tes . 

### BIOLOGI CAL ASPECTS RELEVA NT TO CHLORIM URON- ETHYL The m ode of ac tion of th is h erbicide i s inhi bition of th e e nzyme ace tolacta se sy nthase (ALS )
. S in ce the i ntroduction o f s ulf o ny lu reas i n 1 980 s, ALS inhi bitors s uc h a s c hlorimuron-ethyl we re w idely u s ed in cro p produ cti on ( Patzo ldt et a l , 200 1 ). L o w rate, low ma mmalian to xicity , fl e xibl e app lic ation t iming, an d b road s p ec trum o f w eed co ntrol were the ad vantages of u si ng th e s e herb icide s. However, w ide u s e of AL S inhi b itor s c ontributed t o th e d e velopment of re s istance bi o-t ypes to th e s e herbicide s gr oup . R e sis tant wee d s peci es i nclude : co mmon rag weed s 

### Am brosia ar temisiifoli a , g iant ragweed s 

### ( A m brosi a trifida) , p rickl y lettuce 

### (/ec tu ca s e rriola) , koc hia 

### ( Ko chia s coparia ), s mooth pi g weed 

### (Amaranthu s hybr idus), Liv id amar anth 

### (Amaranthus lividu s), Red s tem 

### ( Ammania auricula ta ) (Her bicide Resistant Wee ds , 2010 )
.
3

### USE TR ENDS F igur e 4 . C hlorimuron Us age o n S oybe ans Soybeans

] 200 ,000 

# " -c ;; 

# £
o 1998 1999 2000 2001 2 002 200 3 2004 2005 2006 2007 2008 Year Sou rc e : GfK Kyne tec, 1998- 2008 T he deve lopment o f resi stant wee d bi otype s, the i ntroduction o f R oundup Re ady s oybe ans, and th e cost eff ective ness o f Ro undup Ready techn ology m ay h ave contribut ed t o th e d ecrease in 

### chlorimuron-ethyl u sage s ince 1998 (C arpenter & 

### G ianessi , 1 999)
. H owever, the tr end d ata (F igure 4 ) h as no t b een full y an alyzed so th ere ma y b e o ther f actors c o ntribut ing to th e p atterns In u sage. 

### HISTORY OF BEAD ASSESSMENTS FOR CHLORIMURON ·ETHYL There we re n o p ast BEAD assess ments o f th is c hemical in the B EA D Official R ecord s 

### DATA NEEDS RELEVAN T TO BEAD'S FUT URE WORK ON C HLORIMU RONETHYL
• Us age d ata (s uch as the a mount c f 

### a. i. u sed and the ac res treate d ) f or th e n on-crop a reas s uch as fe nc erows an d road side s . • Usage data i s n eeded f or cr anbe rries.


### REFERENCES C a rp e nter 

### J. & Gi aness i 

### L. (1999). He rbicide t olerant soy b e an s: Why g rowers a re a d opting Ro undup Ready v arieties
. 

### AgBioForum, 2( 2), 65 -72
. http ://wv...'W .agbi of orum . org/v2n2/v2 n2a 02

- ca rpente r. htm GfK Ky netec . (1 998- 2008)
. Propri etary d ata .
4P atzoldt , W. L., T ranel, P. 

### J
. , A lexander, P L., and P. R.S c hmi tzer . 2 001. A c ommon ragweed p opulation resistant to cl oransulam-m ethyl. Wee d Sc i
. Vo 1. 49 , No .4 , pp . 4 85-490. H erbi cid e Resistan t Weed s. 2 010. http: //www.weedscie nce .orgisummarv/MOASummary .asp

5