UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGT ON D .C., 2 0460 

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### 2010 OFFICE O F PREVE NTION, PESTICIDES A ND T O XI C SUBSTA NCES
MEMORANDUM SUBJ ECT : Review o f a S upple ment to a L abel Ame ndment Req uest for Az inpho s -methyl (DP # 375971) FROM : N i kh il Ma llampalli, En tomo logis t B io logica l Ana ly s i s Branc h



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### J Wya tt , Senior E co n omis t**J1** Eco nomic A na lysis Branc h 

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# 'V fi l 20 10 B iologica l an d E conomic Ana lysis D i visi n (750 3 P) Arne t Jo nes, Ch ief 

# Il B iological Analysis B ranc .r Timothy Kie ly, C hief 

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. ,) Bio logica l and E conom ic Ana ly s i s Div i s ion (7503P) Thomas Harris In secticide and Rodent icide Branc h Registrat ion Divi s ion (7505P) Kat ie Weyrauc h , C hemica l Review Manage r Ma rgare t R ice , C hi ef Ris k Manage ment and Im plem e ntation Bra nch 2 Pesticide Re -evaluatio n D ivis ion (7508P)
BE AD Product Rev iew Panel dat e: Apri l 7 , 20 10 Introduction Unde r th e cance llation agr ee men t for az inpho s -meth y l (A ZM), E PA an d the reg i strant agreed to a deta iled phase -out s c h ed u le for s everal fru it c rops, including app les , b lu ebe rrie s, c h err i e s , and pears (EPA , 2006)
. Th e p ha se -out was imp lemen ted t o a llow growe r s a p e riod of time to
P age I of5id entify a nd tr an si tion to ne w pes t contro l met hod s, i n pa rt b eca u se B EAD es tim ated th at th ere cou ld b e s i g ni fic an t impact s o n grower s of th e s e c ro ps i f AZM were cance lled. U nde r th e ph a seo ut, se aso n a l ap plication rat e s are reduc e d i n s tag es, b eginni ng in 2 0 0 9, w ith u se of AZM full y ca nc e lle d a fter th e 2 012 growi ng s e aso n . Th e r ate redu ction s we re de signed to b egin to a ddre ss th e r i sks po se d b y AZM to work e rs a nd th e e nvironme nt w hile s till a llowing g rowers th e u se of at l ea st o ne applica tion o f A ZM , p e rhap s a s a rescu e tr ea tm ent. In J une 20 09 , th e r egi str ant , M akhtes him A g an N orth A merica (MA NA), s u b mi tt ed an ap plication f or a l abel a mendment t hat wo uld ma intain s easona l ap pli ca tion rate s at th e 20 09 le vel throu gh t he p ha se -out per iod on th e g round s th at i mpa ct s to grow e r s w ill b e s i zeab le. B EAD ev alu ate d th e regi s trant' s s ubmissi o n, a s w e ll as co mment s f rom un i v ersit y e xtens ion p ersonnel, i ndividual grower s an d g rower a ssoci ati ons r eceived in re sp on s e to th e application
. BEAD co ncluded th at th e s ub m iss io n d id n ot prov ide a n y n ew information th at w ould s uggest th e imp act s w ould b e l ar g er than B EA D h ad e s timated a t the time EP A d ecided to c an c el A ZM (A twood 

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. , 2 010 )
. O n M arch 1 5, 2 0 I 0 , th e regi str ant s ubmitted to th e Regi str ation D ivi s ion a n a dditional re quest to c on sider wh at i t cl a ims i s n ew information rel e v ant to th eir pr opo s ed label a mendment fo r tart c herrie s. As w ith th e o riginal re qu est , at i ssue i s w hether an y ne w i nformat io n reg ardin g th e im pact s of c a ncelling A ZM w ould s ugge s t tha t EP A s h o ul d re v i si t th e d eci s ion to lower s easo n al ap plicatio n rate s f o r the remainder of th e pha s e-out period
. B EAD r eview ed th is n ew s u

b mis s io n a nd a gain find s that i t do es not provid e a ny n ew informati o n th at w ould l ead B EAD to re vi s e i t s pr e vi ou s e s timate s o f t he impa ct o f c a nce lli ng AZ M (A twood and Wyatt , 2 0 05)
. D esc ri ption of t he MANA s ubmission T he s ub missio n b y M ANA c o n s i s t s of a n ex plana tory le tter f rom the reg i s trant, in w hic h th ey appear t o f o c u s on th e need f or AZ M a t 2 0 0 9 ap plication r ate s to co ntrol plum c urculio in t art c herrie s. U nd er th e ph a se- out term s , c herry grow er s had bee n able to u se AZ M at a rate of 1 .5 Ib ai /acre pe r ye ar thr ou gh 2 009. Be gi nning in 2 010 a nd c o ntinui ng th rough the e nd of t he ph as eou t in 2 012, th e ap plication rate i s l imited to 0
. 751b ai/ac re p er y e ar. MA NA cl aim s th at th e label a mendment to i ncrease th e la b el rate thr ough the e nd of th e ph ase- out i s n ece s sary to a llow growe r s at lea s t t wo applications , s in ce th e typical us e rate i s 1 lb ai /ac re . Thi s lett er i s f ollowed b y e x c erpts from res earch g rants pr oposal s m ade b y Mic hig a n S t ate Uni ve rsity s c ien tis ts i n re sponse t o USDA

- CS REES g ran ts pro g rams s uch as th e Pe s t Mana ge ment Alte rnative s P rogram (PMA P) a nd C ro ps at R isk ( CA R) program . T he l etter s t ates that the se e xc e rp ts c ons titute a " pro ble m s t ate m e nt/iss ue an aly sis" rel e v ant to th e re que st. B EAD's re sp on s e f ocu s e s o n th e s ubs t anc e o ft he exce rpt s. Th e p o int s m ade in the s ubm iss i o n th at are related to B EA D' s impact a ssess ments appear to be identical to tho s e m ade i n m an y o f th e c ommen t s s ub mitt ed in 2 009. Ma jo r po int s in clud e: M aximum Res idue Levels ( MRLs), whi ch ar e ess e ntia lly international tol er an c e s, h ave n ot b een es tablished f o r all p ot en tial AZM alternatives i n all e xp o rt d e stin ation s and

Pa ge 2 o f5wher e MR Ls ha ve be en es tablished they ma y be lower than tolerances allowed in th e 

### U.S. AZ M ha s th e abilit y t o pen etrate fruit a nd thu s kill pe sts feeding internally as well as e xternally for an e xtended period of tim e (a s o-called 'c urative' po wer). Pho smet ha s s ignificantly lower e fficacy th at AZM, if mix ed in w ith a lkaline water. The plum c urculio i s th e m ost c ritical pe st f or c herries and may not a lways 

### be adequately co ntrolled b y AZM alternati ves. Re search tri als ov er the la st s ix years have s hown more 'failur es' in fi elds treat ed with reduced ri sk alt ernatives s uch as thiameth oxam, s pinosyn, and indox acarb, a s c ompared t o fi elds tr eated with AZM. Failure i s defin ed as any dete ction o f on e of the key pests, es pecially plum c urculio and ch erry fru it fl y, or a s ituation w here the gr ower re sorted to an application o f A ZM or ph osmet. BEA D r esponse BEA D assesse d th e impacts o f the remo val o f AZ M as a pe st c ontrol to ol in 2 005 (A twood and Wy att, 2005 ). Ba sed o n the availability o f effi cacious alt ernatives to A ZM to c ontrol p lum c urculio and c herry fruit fl y in tart c herries, B EAD c oncluded th at the bene fits de rived fro m the u se o f A ZM were likel y to be s mall. In th e absence o f AZM, growers wo uld most l ikely u se pho smet to maintain the local, s tate, and federal mandated z ero tolerance fo r th ese p ests. BEAD c oncluded th at u se o f ph os met wo uld likely raise p roduction c osts by around $ 10 to $ 25 p er acre. Thi s co uld amount to two to four per cent o f a gro wer' s net c ash r eturns ( gross revenue minu s operating c osts). How ever, B EAD al so n oted at th e time that recent incre ases i n the pri ce o f ta rt c herries ma y mean that th e benefit s of AZM as a percent o f net c ash returns would be s maller. BEA D al so noted th at MR Ls were not yet i n place f or a ll the likel y a lternatives at th e tim e o f ass essments, whi ch c ould a ffect p roducers tar geting ex port mark ets. BEA D responded to mo st o f th e points made in th e s ubmission under review in thi s paper , in an other recent memorandum (A twood et al. ( 20 10). To reit erate the rele vant p ortions o f th at response: BEA D appreciat es th e i nformation on th ose ex port markets o f k ey i mportance f or c herry grower s. M RLs for th ese mark ets are being track ed by the A gency and it appea rs that there are level s es tablished f or s ome, but not a ll, AZM alt ernatives in many c ountries importin g U.S. c herries. BE AD noted thi s co ncern f or th e fe asibility o f us ing so me alt ernatives b y growe rs targeting the e xport market but was not abl e to quantify the impa ct. Th e c omments provide no ba sis o n which to qu antify the impact s no w. Re garding the c omments on the failure s of AZM alt ernatives in researc h trial s, BEAD hi ghlights two ca veats a s to the utility o f th e information as it wa s d escribed: 1) A l ack of in formation on th e e xact d etails o ft he " p a ir ed co mparisons" between AZ M and th e redu ced ri sk alt ernatives means that BEAD c annot u se th e data to d etermine wh ether th e 2 005 a ssessment o f th e utilit y ofJikely c ombinations o f s uch alt ernatives a long w ith o ther co nventional m aterials ( such as lambd a-cyhal othrin , a sy nthetic py rethroid, and ph osmet, an or ganophosphate) was signi ficantly in correct.



### Pa ge3 o f52) Based on the information p rovided in the comment , it i s not possible to extrapolate from the number of failure s s een in re search trial s of reduced ri sk material s to the larger grower community in a reasonable manner . For example , how can the results be u sed to d etermine the frequency of s uch failures in c ommercial production , es pecially wh ere c ombination s of redu ced ri sk and conventional in secticides are likel y to be u sed? Since th e cit ed failure s w ere s een in fi elds where either a s uite of ' reduced ri sk' (RR) or ' OPalternative ' in s ecticid es had been us ed, the information cannot reasonabl y be us ed to predict whether o r not increa sed failure s are likel y to occur w hen pho smet is u sed, either alone or in combination with a s ynthetic pyrethroid or neonicotinoid in secticide. In fact, in a previous submi ssion citing th e s ame re search trials , failure w as defined as " RR and Oft-alt
. orchard s that re sorted to OP- sprays (AZM 

### or phosmet) , and known failure s that did not s pray" (Whalon , 2 009, empha sis added)
. Furth ermore, B EAD 's 2005 a ssessment acknowledged that pho smet was le s s eff ective than AZ M and may requir e multipl e a pplications and that synthetic p yrethroids may reduce popul ations of beneficial in sects. Pho smet a nd s ynthetic pyrethroids may have di sadvantage s relative to AZM, but failure to include them a s po ssible control mea sures ov erestimates the impact s of the l os s of A ZM. Regardin g th e ineffectiv eness of phosmet when used in alkaline c onditions, BEAD note s that this c onstraint exi sted at th e tim e of it s impact as sessments in 2005 a s well. Thi s i ssue continu es to be highlight ed in e xtension service advic e to g rowers. For example , the Michigan State U niversity Fruit Management Guide (M SU, 2010) mention s the importance of keeping pH below neutral ( 7). Despite thi s limitation , pho smet wa s , and s till i s , recommended a s an option for plum c urculio (and o ther p est) c ontrol (Wi se et al. 2008 , MSU 2010). B EAD acknowl edges that so me c ontrol f ailures w ith pho smet may occ ur , but the informati on a s pro vided in the M ANA l etter doe s not pro vide a b asi s on whi ch to revise the 2005 impact a ssessments. Re garding th e "curative ' power s of A ZM, B EAD note s that oth er in secticides regist ered for u se against plum cur culio in cherrie s, are s uggested to gro wers i n at lea st one recent Michigan S tate University publication ( MSU 2 008) be cause of their own c urative abilitie s. Pe sticides mentione d a s ha ving thi s abilit y include phosmet and the neonicotin oids acetamiprid ( Assail @) , thiaclopri d (Ca lypso ® ), and thiam ethoxam (A ctara ® ). B EAD acknowledg es that the reduction in appli cation rate s of A ZM in 2010 ma y lea ve grower s w ith only one s easonal treatment with th e material. However , th e availabilit y of these other " curative' option s (alon g with s everal oth ers that have onl y ex ternal c ontact toxicit y , s uch a s syn thetic pyrethroids a nd indoxacarb, an oxadi azine) indicate s to BE AD that grower s ha ve s ome effe ctive, relati vely new avenues for plum c urculio c ontroL S uccess of pe st c ontrol with th ese altern atives depend s, of cour se, on continuin g re search and grower e ducation throughout th e pha se-out. Finall y, B EAD e xamined data on AZM appli cation rate s in Michigan cherry production to determine if the label rate of 0 .75 lb ai /acre would impo s e unanticipated impact s o n grow ers during the final years of the pha se-out. Data are f rom a marketing surve y conducted annu ally b y G fK Kynetic and follow s tatistically v alid coll e ction proc edures. Data from 2006-2008 , w hich wa s prior to the s tart of the pha se-out, indicate that th e applic ation rate i s at or below O .751b ai /acre on n early 98 % of the Michigan cherr y acre s treat ed w ith AZ M
. Thu s , BE AD co ncludes

Pa ge4 0f 5that the c urrent allowab le rate o f 0 .75 Ib ai/ acre i s s ufficient to pr ovide a " rescue" tr eatment f or the duration o f the pha se-out if an alternati ve c ontro l reg ime w ere to f ail.
Cit ati ons A twood, D., and T
. Wyatt. 2005
. 20 05 G rower Impact Ass essment of Azinph os -methy l Us e on Tart C herries (DP 3 07589). Avai lable at www .regulations.gov
. A twood, D., D. Bra ssard, N. Mallampa lli , S. S mearman, and T
. Wyatt. 2010. Re view o f a Lab el Am endment Request for Az inphos

- methyl , incl uding Pu b lic C omments ( DP 

### # 3735 59). A vai lable at www .regulation s.gov . EPA. 20 06. Fina l Decisions f or the Remaining U ses o f Az inphos

- methyl. O ffice of Pre vention, Pe sticides, and Tox ic S ubstances, Nov ember 1 6. A vailab le at http : //www .epa.gov /pe sticides/reregi stration/azm /azm rema ining u ses.pdf. MSU. 20 1 0. M ichigan Fru it Managem ent G uide ( 2010). Extension B ulletin E

- 154 o f t he Michigan S tate University, Eas t Lans ing , Michigan
. 144 pp
. Whalon , M
. 200 9. G eneral c omment. Departm ent o f Entomo l ogy, Mi chigan S tate U niversity. A vailab le at www .regulation s.gov , d o cket EP A-HQ- OPP-2009 -0 365, document 0 022. Wi se, J ., N. Roth well, D. E pstein, L. G ut, and M. Whal on. 2 008
. O ptimizing in secticide s prays for p lum c urcu l io. Fruit Crop A dvisory T eam A lert Ne wsletter, Vo l 2 3 ( 7): pp 2

- 3. Av ai lable o n the w eb at : http :/ /www.ipm .msu.eduJcat08fruit/f05

- 20 -08 .htm
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