UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D .C., 2046 0

MEMORAND UM 

### JUN 0 9 2 010 OFFICE O F C HEMICAL SAFETY AN D POLLUTION P REVENTION

S UBJE CT:

FROM:

T H RU :

TO : E valuation of a Requ est fo r a Pub lic Intere st Finding f or the Co nditional Re gi strat ion of Am in ocy cl opyracW or an d A m inocyc lopyrachlor Methyl fo r Weed and Bru sh Co ntrol ( D P#37 6722) 

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Wi lliam Phillips , II , Ph .D. , A gro nom i st B iolog ica l A nalysis Bran c h Biolo gica l and Econom ic Analy sis D ivision (750 3 P ) 

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- ' Q:/ Arn et Jone s , C h ief**~v** v j Biologic a l A naly sis Bran ch B iol og ical and Econ omic A na lysis Div ision ( 3 P) M indy O ndish Her bicide Branch Re gi strati on Divi sion ( 7 5 0 5P )
PROD UCT REVIEW PANEL : June 02, 2010

S UMMARV A request w as s ubmitted to the U nited State s Environm en tal P rote c tion Agency ( Agency) b y the regi strant E .I. DuPo nt d e N emours and C ompany ( DuPont) t o d etermine whether a reque s t f o r the con ditional re g i strati on o f a n ew a cti ve in gred ient fo r the broad leaf her bicide am in ocy clo p yrachlo r a cid ( DPX

- MAT2 8) and meth yl ( DPX-IU M 44) ( aminocyc lopyrachlor) is i n the pub lic interest. The herbi cide will be u sed in t ur fgras s (TG) and veg etat ion m an a gement ( V M) are as suc h a s ri ghts-o f

- way , f ence ro ws. ditch bank s. wildlife are as , n ative gr a s s and turf ar eas . Th ere w il l be 1 5 e nd-use produ cts and 5 te chn i cal ac tive i ng redien t s (1 5 E Ps and 5 TGA IIMUP)
. Such a p ubl ic i ntere st fi nd i n g ha s m an y c omp one nt s; howeve r, B EAD ' s ro le i n th i s proce ss wa s t o f oc u s on de termini n g if the re i s a need f or thi s new pe sticide t hat i s n o t c u rre ntly be ing met by r egi st ered p esti cide s and if t he be nefi ts f rom the new pes ticide are greater th an thos e f rom c urre n tly reg istered p e sticid es or non- c hemi ca l contro l mea sures .

1Overa ll, the data s ubmitted was in complete wit h r espect to herbicide e fficacy co mparisons an d da ta ri gor, an d as s uch, the i nformat ion provided by the r egistrant fo r ami nocyc lopyrac hlor fai led to m eet th e requirement that the he rbicide co ntrols wee d spe cies th at are not co ntrolled by c urrently reg istered h erbicides. W hile mentioned i n the reg istrant's s ubmission, but not a primary fo cus, th e vo latility o f 2,4 -0 an d di camba i s imp ortant to co nsider whe n b eing u sed arou nd va luable orname ntal pl ant m aterials. Beca use th ese two h erbicides a re a s taple of th e com mercial turf in dustry, i f fie ld use o f ami nocyc lopyachlor i s de termined to h ave a lower vo latility than 2,4 -0 o r d icamba it w ill be i mportant to c onsider this po tential a dvantage as m eeting th e cr iteria th at there is a b enefit of th is herbicide regis tration ove r those from c urrently registered h erbicides or non -chemical meas ures. F uture d ata s ubmissions provided to B EAD w ill be eva luated to de termine i f aminocyc lopyrachlor meets th e two c riteria: 1 ) that th ere i s a n eed fo r t he n ew pesticide th at i s no t b eing m et by c urrently r egistered p esticides, or 2) that th e b enefits f rom th e n ew pes ticide are greate r t han th ose from curre ntly r egi s tered pesti ci des o r no n -chemical contro l m easures . Until more i nformat ion is p rovided rega rding results of e fficacy t rials , BEAD i s un able to dete rmine if th is h erbicide mee ts these c riteria.

PUBLIC INTEREST FINDING POLICY FIFRA sec tion 3(c )(7)( c) aut ho r izes t he issuance of a conditiona l regis tration for a n ew pes ticide w ith spe cific r estrictions
. T his i nterim r egistration a llows te mporary use of a p est icide w hile fu ll reg istration i s being pursued. A ll three of t he follow ing co nditions mus t b e me t fo r a co nditional reg istratio n to be granted: 1) in sufficient t ime h as e lapsed f

or th e ge neration of da ta , s ince th e requ irement fo r that da ta was i m posed ; 2) use of the pest icide wi ll no t cause unreas onabl e a dve rse e ffects; and 3) u se of t he p esticide i s i n th e p ublic in terest. T he co nditional registration of a new p esticide ingre dient i s pres ume d t o b e in th e publi c int erest if o ne or more o f the f ollo win g c rite ria are app licable. I ) it in vo lves a rep laceme nt fo r anot her p esticide t hat i s of con tinuing co ncern t o th e Age ncy; 2) it invo lves a use fo r w hich a sec tion 1 8 e merge ncy exe mpt ion has b een g ranted, if th e b asis for the exem p tion was th e l ack o f a s uitable a lte rnat ive; o r 3 ) it in volves a use against a pest of p ublic h ealth signi ficance. Fo r p esticides th at do n ot m eet th e cr iteria li sted above fo r t he pr esumption of p ublic int erest, o n e of the fo llowing three cr iteria m ust b e m et. 1 ) th ere is a n eed for the ne w pe sticide t hat is n ot being m et by c urre ntly regis tered pes tici des, 2) th e n ew pes t icide imposes l ess ri sk to h uman h e alth and t he e nvironme nt than c u rren tly r egistered p esticides, 3) b enefits f rom th e n ew pestici de are greater than those from curren tly reg i stere d pestici des or n on- ch emi cal co ntrol m easures . To de termi ne if the crit eria are m et w ith r espect to curre ntly regi stere d pesti cides, BEAD 's rev iew f or thi s p art of th e publi c interest fi nding (PIF) w ill foc u s on item s I a nd 3
.

2P J;BL.lC INT EREST FINDIN G REQUEST Du pont , the re gi s trant of the herbi cide amin ocycl opyr achlo r , ha s reque sted that the Agency review its s ubmitted in formation to determ ine i f a c ondit ional re gistration of th is h erbicide i s in the pub lic i ntere s t. I n s uppo rt o f it s re quest fo r th e Agency' s rev iew fo r co nd itional reg i str ation, B EAD h as received the following in format ion : I
. a s tatement in s upp o rt o f a publi c i nterest fi nd i ng 2. a l ist of u niver s ity in vestigat ors 3
. a s ummary report of comparat i ve effi cacy d ata for s ome of th e more d iffi cult to c ontrol w eed s pec ies that wi ll appear o n th e product labe l s 4 . 1 5 end -use prod uct labels a nd 5 techn ical act ive in gredient labe l s (15 E Ps an d 5 T GAIIMUPs)
. The re gistrant h a s s ta te d that the prim ary b asis fo r its reque st f or th e V M registration is that t his new herb icide will contro l certain inv asive and noxious bru sh wee d s pecies tha t no c urrently regi stered pes ticides c o ntr o l s . The b asis f or the TG u se re gis tration i s that t his he rb icide h as a h ighe r effic acy o n difficult to man age bro adleaf weed s pecies ( BLW ) a s well a s herbicide resi s tant BL Wa s compared to o ther reg i stered herbicide s. Sec ondari ly , for both o f the se ge nera l use s ites th e re gi s trant m aintains t hat it s he rbicide w ill r educe t he am ount of pesticide s u s ed to cont rol b rush an d TG s pecies d ue to i t s lower u se rate . T he r egistrant believe s th at togethe r the se s tated benefit s of am i nocycl opyra chlor make it i n the pub lic inter est to g rant t he c onditional re gistration
.
BIOL OGI CAL**A~ALY St**  ISTROD U CTION A minocyclopyrachlor i s a p yrim i dine c arboxylic aci d s that be long s to th e f amily of sy nthetic au xins
. Th e herbic ide label s wi ll includ e u ses in go lf c ourses . sod producti on , re sidentia l turf , and o ther TO u ses as well as VM are as , w hich wi ll in clude ri g ht s -of -w ay . f e nce rows, ditch bank s , wild life ar eas, an d nat ive gras s a reas ( Tab l e I )
. Labeled rate s and maxi mum numbe r o f applicatio ns wi ll b e 0 .284 I b acid equ ivalent (ae) ! A with an annu al m aximum o f o ne ap p l ication fo r VM , an d 0
. 108 lb ae ! A w ith a m aximum of thr ee applic at ions o r a total annu a l amo unt o f 0.324 1b ae/A for TO
. A pp lication met hod s wi ll include ground b oom for both si tes , wi th the addi tion o f aeri al and basal b a rk applicat i o n s, in

jec tion, c ut-surf ace, soi l app lied , an d cut s tubb l e /s tump app lic ation s for VM
. Label s for th ese p roducts will i nclude li s t s of wee d s pecies c ontro ll ed th at wi ll includin g w eeds v arying fro m s mall annua l we eds to tree an d bru sh s pecies
. The u se s ites an d weed s pectrum are s imilar to th ose o f o ther he rbicides i n the sam e c hemical f amily ( T able 2 ).

3

### Tab le 1
. A minocyclopyrachlor h erbicide r eque s ted use sites f or the co ntrol of an nual , broadleaf and brus h wee d specie s. Sites for Use Ex amples o f S pecific Sites U ncultivated Private , pu blic and military l ands such as airports, hi ghway , railroad and Nonag ricultural u tility ri ght s- of-way , sewage di sposal areas , e tc .); Uncultivated Agric ultural area s Indu s trial sites N atur a l areas
Release or Res toration Residen tial Turf Industrial and Professiona l Turf N on - c rop pro ducing

- s u c h as farm yards, f uel s torage area s, fencerow s, n on-irrigation d it c hbank s and wate rway s (d e -watered) , barri er st rip s, e tc. Lu mberyard s, p ipeline , tank f arm s, e tc . Wi ldlife management areas, w ildlife ope ning s, wi ldlife habitat s, recre ation areas , campgrounds , trail heads and tr ail s Nati ve p erennial grasses
Lawn maintenance - h erbic ide / fertilizer c o m bin ati o ns Unimproved turf e stab li s hed arou nd manufacturing and i nd u st rial area s as we ll as e s tabli s hed turf i n go lf course s, athletic fie ld s, s od farms , and re s ide nce s.

4

### Table 2 '. Selected potential alt ernative herbicide s to arnin ocyclopyrachlo r Herbicide Sites Weed s C ontroll e d Aminocyclo py ra c hlo r R ang eland
. permanent g ra ss, p astures. Annual and Per ennia l B roadleaf W eed s and r igh ts-o f-way
. roa d sid es. an d non -i rrigation W ood ylBru sh S peci es

ditch bank s, w il dli fe m ana geme nt areas. n atura l r ecreat ion areas , c am p grou nd s. trailheads. tra ils. an d tu rf ( crop, gol f, a nd resident ia l) Amin cpyralid

B romacH"

2,.1-0 ' -

D icamb a

P i cloram"

M ec o prop

Clopy rlid
Gl yphosate

Imaz ap yr R an g eland , permanent gr ass, p asture s , r ig hts

- o f

- way , roads ides , an d n o n- irrigation ditc h bank s , w ild li f e m anagement area s. n atural recr eation are as, c am pgro und s. nailh ead s, and tr ails C ulti v ared and Non -crop l and. and i ndustrial s ites Aq ua t ic . cultiv ated an d fall ow cro p land , p as ture . i ndus tria l, C RP l and, tu rf {crop. g olf. and re sidentia l) C ultivated and f allow c rop l and, p asture . industria l, C Rr land , turf (crop, golf. an d re sidental) Rangel and , perm ane nt grass , p astur es , f orestry , righ t s-of-wa y. road s ides. an d n o n irri gati o n ditc h b ank s. w ildli fe man agement areas. n atura l recre ation areas , campgrou nd s. tr a ilhead s
. trai l s and fo rests C o m merci al and R es i d ent ial Turf R angelan d
. pe rmanent grass , pasture s, fo res try , rights-o f- wa y, ro adside s, N o n -erop and i ndu st rial s ites C ultivate d and fa ll o w c rop land, pasture , indu st rial , C R P lan d A quatic, ran geland , pe rmane n t gr as s, p astures , right s-of-way , r oadsides, a nd nonirrigat ion ditc h b ank s, w ildlife m an agement are as. n atural rec rea uon areas. c ampg ro und s.

nailh ead s. t rail s. and t ur f'(c rop , go lf, and res ident ial)
. man y ot h ers C u lti vated and fall o w cro p l an d. f or es t!')'
. ri ght s -of -way . road s ide s. and non -irrigat i on d itch banks, w ildlife manage ment ar e as Annual and Per enn ial Bro ad1ca f W eed s and W ood ylBru sh S pecies

Annu al and Per ennial B ro adle at w ced. Grass w eed s, Sedg es. and W oodylBru s h Specie s A n n ua l and P e ren n ial Broad leaf W eed s a nd Wood ylB ru s h S pecies
Annua l and P ere nnial Broad Je afWe eds and B ru s h S pecies
Annu al an d Per ennial Bro ad1eaf Weed s an d W ood ylBru sh S pecies

An n ua l B road lea fW eed s Ann ua l and P e renni al Broad lea fW eed s an d Wood ylBru sh Specie s
Ann ual and P erennia l B roadlea fW e c d s a nd W ood y lB ru s h Specie s Ann ua l and Pe ren nial Br o adte ar w ccd
. G ras s W eed s, Se dges , an d Wood y /B rush S pe ci es

An nual and P eren ni al Bmadl eaf and Grass W eed s an d Wood ylBrush S pec ie s N ote : Si te s and weed s c o nt rolled are not c om prehen s ive li s t s. ' H e rbi cid e H an dbook. W eed S cience So ciety o f A mcrica
. E i ghth Ed it ion-2002 , We ed S cien ce Societ y. 8 10 E
. 10 th S t reet. Lawren cc .KS 6604 4 -889 7
. U SA "S pecifi c h erbi cides discu ssed b y reg ist rant as bein g a " R eplacement o f H igher U se Ra te Produ ct s," ( See reg istrants s ubmission: R .M. Ashle y . DuP ont C rop P rotection Su bm iss ion , Publ ic int eres t fin din g stat ement in s upport o f regi s tratio n i ng re d ient s, amin ocy clop yra chlor a nd aminoc yclop yra chlo r m ethy1.)

5D ISC USS I01\ The registrant ha s s tated th at the prima ry b asis for i t s reque st f or th e V M reg i s tration i s th at am inoc yclop yr achlor herbicide w ill con trol c ertain inva si ve and noxious bru sh w eed s pe c i es tha t no c urrently reg i stered pe st icide s c o ntroL Th e ba sis for th e T G u s e re gi str ation i s that th i s herbi cide h a s a hi gher effi cacy o n d ifficult to mana ge broadleaf weed s pec ies as co mpared to o the r regi stered herbicid e s. Seco ndarily, f or b oth o f th ese u s e s ite s, th e regi strant maint ain s th at it s herb icid e wi ll r educ e th e am ount of pe s ticides u se d to co ntrol bru sh in V M and T G are a s due to it s l o wer u se rate . Th e registr ant b eli ev e s th at toget he r th ese s tated benefi t s o f am inocyclopyrachlor m ake it i n the publ ic inter e s t to grant th e co nditional regi s tration
. Effi cacy and Alternat ives T he e fficacy d ata pro vided b y the reg i s tra nt w as a c o llec t io n of tria l r e sults f rom 24 univer s ity re se archer s. Th e inf ormation included on ly mean s f or t rea tm e nt s se l ected f rom thes e h erbicide tri als a nd n ot th e raw d ata. T he r e s ult s w e re n ot s t atis t ic a lly e va luated acro ss t rial s. In o rde r t o f acilitate a co mparative a ss essme nt , a s tatistical an alys i s w as nee ded
. It i s f or thi s reas on th at BEAD' s rev ie w o f the e fficac y d ata re garding t hi s h erbicide u s e in VM and T G d ata c an onl y be di scu ss ed o n a cur so ry l evel. It i s und e r s tandable th at it w o uld n ot b e p ractical f or the reg i s trant to s u b mit a ll o f th e uni ver si ty r e se arch tr ial re sults to the A ge n cy fo r e valuation , n or w oul d th e Agency be abl e to eva luate a ll o f th e i ndi vidual re se arch rep ort s. H owever , g i ve n th e data s h ee ts th at wer e p rovide d it i s cl ear that th e r egistrant h a s acce ss t o, and mo st likel y o wner s hip o f, th e tr ial d at a and s ho uld be ab le to u se thi s d ata to co ndu c t so me ty pe o f meta-anal ysis i n o rd e r to pro vid e s o me s tatis t i cal ri gor to their h erbi cide co mparison cl aim s. B EA D wo uld e va luate thi s t ype o f analy s i s if it w ere to beco me a va ilabl e. As s t ate d e arlier, th e b asi s f or t hi s reque st i s s pe c ifi c to th e tw o g e neral u se s ites, V M and TG for thi s herbi cide
. The re se arch e ffic acy d ata th at wa s s ub m itte d in clud es we ed s p ecies th at oc c ur in b oth VM and T G s ites as w ell a s b ru s h s pecies that are key in V M s ites. T he s pe c ies found i n both s ites are m are 's ta il, ru ssi an thi stle s p ecies, koc hia , knap weed s p ecies, and leaf y s p ur ge. In t hese st ud ies, amin ocyclopyrachl or wa s g ene rally a pplied a s a foli ar s pr ay, but application s to bru sh s pecies incl uded b asal bark treatme nt s; h o wever, d ata w as not s ubmitted f or th e o ther appl ication type s that w ill app ear o n th e VM p roduct l abel s ( e. g . inje c tion , cut
- s urfa ce , s oil ap pli ed, c ut s tubb le/s tump). A n attribute that the reg i s trant s tates i n it s application i s that t hi s herbi cide can

, · ... cont rol i nvasive and n o xiou s w eeds whil e a ll owing n ativ e gra sses an d o th er pla nt s to flouri s h, provid ing d esira ble un d erstory f or wild l if e." However , there w as n o i nf orm ati on or d ata pr ovided r egarding t he i ssu e s o f n ative gr ass s afe ty or " Flashback " ( pa ss ive loss thr o ugh root s ) f rom the c o ntrol of bru sh w he n re storing eco sys tem s an d/or nat i v e habit at s. The se are c on s ideration s wi th o ther herbi cides in thi s c hemi ca l f amily a nd ma y need to be eva luat e d f or thi s he rbi ci de
.

6The p rimary b a sis f or the regi str ant' s r equest fo r th e VM registration is th at this new h erbicide w ill control certain invasive and nox iou s brush w eed spec i es th at no c urrently regi s tered pe s ticide s con trol. Speci ficall y s tated, 

### "Aminocyclopyrach lor also provide s excellent contro l 

### 0/ a number of brush spe cies including Box elder ( Acer negundo ), Hackberry ( Celtis o ccidentalis), a nd Sugar berry ( Celtis laev igata) that current ly are not being effect ively contro lled by any other regist ered brush herbicides or herbicide programs." Thi s s tate ment sho uld be cons idered un der th e fi r s t c riteria w ith w hich B EAD i s c harged, t hat th ere is a nee d for th e new p esticide t hat i s no t b eing m et by c urrently r egistered pesticides. Severa l herbicides i n Table 2 are in th e sa me fam ily as am inocyclo pyrachlor and have th e s ame basic we ed s pec trum. Da ta o r in formation f or a f ew of th e s e herbicides and their relative effica cy we re p rovided in the trial resu lts s u b m itted b y t he reg i s trant. T he herbicide s that liste d i n Tab le 2 that were included in the li st of trial data were n ot in cluded in a ll tr ial s, n or f or a ll s pec i es te st ed. I n man y c ases, the comparative e fficacy of m ost of th e s e h erbicide s wo uld have be en important i n order to eva luate th e e ffi cacy of thi s h erbicide
. T he only m anner wi th w hich to co n s ider th e compara tive efficacy o f th is herbic ide i s to d iscu ss the relative perce nt weed c on trol u si ng th e ind u stry s tandard of an accep table c o n tro l level o f > 70 %
. Howev e r giv e n th e u ncertainty regard ing t he re lativ e na ture o f t he data, in thi s docu ment the standard of > 80% w ill be used. T h e only h erbicide t hat does app ear con sis tently thro ughout t he e ffi cacy pac kage sub mitte d i s i mazapyr . Beca u se the reg i stra nt s ingled out the three bru sh s pecies (box e lder , h ackberry, an d s ugarberry), th e d i s cu s sion be low i s f ocused on these s pec i es. Da ta for other bru sh speci es wa s i nclud e d in the regi s trant 's s u bmission; howeve r, t he da ta f or these specie s followed the s ame method of e valuat ion and data prese ntation by the registrant, and o ve rall did not y ield res ults m uch di fferent fro m for tho se specie s below. Based on the reg istrant' s s u b mi tted data , box elder contro l wi th am inocyclo pyrac hlor was > 80% as we re i mazapyr and ami nopyralid
. Herbicide s that wou ld a ls o be cons idered a s po tential a lternative s s uc h as tho se in Table 2 were n ot i ncluded a lone i n the da ta, o r we re i ncluded b ut o nly in combination w ith am inocyclopyrach lor
. Hackberry was anothe r s pec i es eval uated wi th i mazapyr b ut wa s no t eva luated w ith o ther potential a lternatives. In thi s grou p of da ta, i mazapyr contro l wa s < 80 % w hile th e regi str ant 's h erbicide was great er . Ap plications made to s ugarberry includ ed imazapyr, which did not meet the s tandard of 80% contro l as d id aminocyc I opyrach lor . While th e data p resented f or th e three 

### "i nvasive and noxiou s brush weed s pecies" indica te s pe rhap s w hat i s probab ly good to exce llent cont rol, the data is incomp lete with respect to herbicide co mparisons and data rigor, and a s s uch, fail s to ind icate that aminocy clopyrachlor contro ls bru sh weed s pecies th at are not co ntrolled by curre ntly regi ste re d h erbicides
. T he data does seem to i ndicate that th is herb icide w ill b e an importan t compon ent in an integ rated pest mana gement program , along wi th other h erbicide s i n this c hemical fami ly.

7The b asis for the T O u se re gistration i s that thi s herbicid e ha s a high er e fficacy o n difficult to c ontrol br oadleaf w eed s pecies a s c ompared to c urrently regi stered herbicide s. Th is s tatement s hould be c onsidered under the fir st crit eria wi th whi ch BEA D i s char ged that th ere i s a need f or th e new p esticide th at i s not b eing met b y c urrently r egistere d pe sticides. The reg istrant di scussed th e com parative effi cacy o f its c hemical w ith respect to picl oram, br omocil , and 2 ,4-0
. In th e c ase of pi cloram th e registrant s tated that " [t] h e w eed a nd brush s pectrum o f amin ocyclopyrac hlor has demonstr a ted cl o se , 

### if not equivalent, cont rol o f the s e s p ecies to piclor am a t use rates u p to 4 ti mes lower than pi cloram
. " Th e c omparison mad e f or bromo cil wa s that "[ ilt is es pecially useful in s i tuations whe re there a re ALS resis tant s pecies s uch a s m arestail , pigwee d , koc hia and R ussian this tle. am inocyclopyrachlor has s im ila r a ctivi ty o n th e se A LS re sistant species a nd w ould be use d at a m uch lower use rate for c ontrol o f these tolera nt sp ecies as co mpared to Bromacil." A s f or 2 ,4-0 , ''" [a ] minocyclopy rachlor h a s a s im ilar ra nge o f s p ec t rum on broadle af weeds a nd supe rior c ontrol of ha rd to c ontrol specie s i nclud ing leafy s purge, Se ricea lespe deza, the thistle co mplex, a nd knapweeds , and wou ld be use d a t a lower use ra te than 2, 4-D
. Giv en the s tatements in their s ubmitted appli c ati o n , th e re gistrant pro vided co ntradictory inf ormation th at th e herbicide c on trol s w eed s pecies that are not controll ed by curre ntly reg istered h erbicides. Ho wever, th e u s e o f thi s h erbicide along w ith oth ers in thi s chemical famil y in co ntrolling A LS a nd g lyphosate re sistant s pecies w ill b e important.

P EST IC I DE RE DUCT ION Th e second b asis f or which the re gistran t ha s f ocused o n i s th at it s herbicide w ill redu ce th e amount of p esticides u sed to c ontrol V M a nd TG wee d s pe ci es i s du e to its lower u se rate . Whil e th is s tatement s eemingly meet s th e c riteria th at the b enefits fr om the ne w p e sticid e r egi stra tion exc eed tho se from c urrently re gi stered pe sticide s or no n-ch emical co ntrol m ea sur es, th is qu alification wo uld m ake it n ece s sary to d eter mine wh ether th e v olume o f a pe sticide produ ct i s related to toxi city. It i s, h owever, o ut o f the purvie w of B EAD to di scus s th e toxic olo gy o f a p esticide; B EAD d efers to th e Env ir o n me ntal F ate a nd E ffect s Di vision and the H ealth Effe ct s D iv i s ion f or thi s det erminat ion
.
H erb icide Chemistry Iss ues As co mpared to h erbicides u sed in T G and V M , thi s h erbicide differ s o nly s lightly in i ts mechani sm o f action but not in it s mod e of action. The mech anism o f act ion for amin ocyclopyrachlor i s the alterat ion o f g ene e xpression , whi ch i s t he same as for the benzoic ac ids, ph enoxys, and the p yridine car boxylic acids. However , the registrant s t ate d that th e m echani sm o f acti on for thi s h erbicide i s th at " [t] h e h erbicide has unique fe ature s act ing via a di st inctive m echanism th at tar gets afam ily of a uxin re ceptor c om plexes
. " The mode o f ac tion f or amino cyclopyrachlor i s unc ontrolled c ell di vision an d gr owth, whi ch is th e s ame as th e benzoic ac ids , phen oxy s , and pyri dine c arboxylic ac ids
. Wh en c omparing th e m echanism and mode o f acti on of the herbicide s i n thi s c hemical f

amily , th ere i s littl e di fference. The re gistrant s tated, ho wever , that aminocyclopyrachlor i s

B"
. .. non-vo latile and c ont rol[ s] mo st bro adleafw eed s in tu r f wit hout the nee dfor ph enoxy her bicide s." A s tud y c onducted b y S trachan et al l c ompared the vo latility o f amin ocyclopyrach l or meth yl with di camba , and amin opyralid
. T he r e s earch c oncluded that th e active ingre dient did i ndeed h ave a l ow vo la tility i n t he l ab o r a t ory ; however, when mi xed wi th methy l ated s e e d o il ( M S O) under the s ame laborato r y c ondition s th e vo latility o f ami nocycl op yrach lor me thy l was c o mp arabl e to that o f dicamba
. Wh en the s tudy wa s rep licat ed in t he field th e e ffect s o f amin oc ycl opyrachlor + MS O o n s o ybean and k idne y b ean was lower than dicamba
. Th e co nclusion o f the re search wa s t hat ther e n e eds to b e m ore re s earch to und er s tand th e v apo r move m e nt o f amino cy clopyrachlor u nder fi el d c o ndition
. Th e u s e o f a n he rbicide fo r BL W co ntro l on g o l f co urse s and re si dentia l u se s ites w ith a low v olat ility redu ces th e phyto x ic e ffe c t s to v a l uab le o rnamental p lant s . fffieid u s e of aminocycl op yachlor demo n s trate s a l ower vo latility t han 2 ,4-0 o r di camba i t w ill b e i mportant to co n s ider thi s p oten tial adva nta ge as meet i ng th e c riteria th at ther e i s a b enefit of thi s herb icide re g i s tration ov er th o se fro m cu rr e ntl y re gi stered h erb icide s or non -che mica l mea s ur es. B EAD d ef er s t o RD , EFE D, andlor H ED to mak e thi s de te rmination
.
CO N CL U S I O :ooiS A ND FINDl J'Il GS Ov e rall, t he d ata su bmitte d wa s i ncomp lete wi th r e s pe c t to herbi cid e e ffi cacy c o mp ar is o ns and s t at is t ica l d ata rigo r , an d a s s uch , th e i nf ormation pr ovid ed b y th e r egi str ant f or ami noc yclop yrach l or f ailed to m eet the requ irement th at t he herb icide c ontrol s w eed s p ecies th at are n ot co ntrolle d b y c urr e ntl y re gi stered h erbicide s. Regardi n g the s eco n d b a s i s f or w hich th e r egi strant f ocused , th e d etermination th at a re duction i n th e a mount o f pes ticide s u se d to c o ntro l w eed s p ec i es d ue to thi s herbicid es lower u se r ate i s not in th e p urvi ew o f B E AD
. Th i s u s e rate reduction be nefit cl aimed b y the regi s trant ma y b e f ocus on a reduc tion i n e nvironmen tal l oading o f pe st icid es. B EAD defe r s to t h e En v iron m e ntal Fa te a nd E ffe c ts D i v ision and t he Hea lth E ffects D ivis i o n for t hi s d e termination
. Th e p oten tial low v o la ti l i ty o f thi s h erbicid e i n TG c o uld b e imp ortant i n g ol f c o urses and o ther site s wh ere diffi c ult to co ntrol B LW s pecies ar e ne ar and arou nd ex pe nsive o rnamental p lantin gs. W hile mentioned i n th e re gi strant' s s ubm ission, b ut n o t a p rimar y foc u s , th e v o latil ity o f2 , 4-D an d dica mba i s im portant to c on sider whe n b ei ng u se d aro und va luable o rnam e nta l p l ant materia ls. Beca u se the se tw o h erbicide s are a s t ap le o f the co mme rci al turf indu stry , i f fi el d u se o f aminoc ycl opya c h io r i s determined to h a v e a lowe r v olatilit y than 2,4- D or d icamba i t wi ll b e impo rtant to c on side r th i s be nefit as meet ing th e cr iteri a that t here is a b en efi t of thi s herbicide re g i stra tion ov e r t ho se fr om c urrentl y r e gis tered herbi c ide s or non- ch emi c al m easure s . BE A D d ef er s to Regi strat ion D ivi sio n , E nv ironmen t al Fat e and E ffects D iv ision, and t he He a lth E ffe c ts D ivision o n thi s de termin a tion
.

1 Str acha n , S .D ., M
. S
. C a s in i, K .M. He ld reth , J
. A. Scocas , S J . N isse n, B. Bukun, R.B . L indenmayer , D.L. Sh aner , P . Westr a , an d G. B ru nk. 2 0 1 0
. V apor m ovemen t of s ynthetic aux i n h erbicid e s: am inocyclopyrac hlor , amt nocy clopyrachlor- methyl, dic amba, a nd am in o pyralid
. Weed S ci. 5 8 : 10 3 -1 08

9F uture d ata s ubmissio ns pro vided to BE AD w ill be e va luated to dete rmine i f amin ocyciopyrachlor me et s the two cri teria : 1 ) that ther e i s a need f or th e n ew p est icid e th at i s not b ein g m et by c urrently re gi st ered p esticide s , or 2 )that th e b enefit s from th e n ew pe sti cide ar e g reater than t hose fro m c urre ntl y r e gistered p esticid e s o r n on- c hemical co ntrol m eas ure s. Until m ore in formation i s provided r egarding results o f e ffi cacy tri als, B EAD i s unabl e to det e rmine if thi s herbicid e meets th ese c rite ria
.

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