# Registration Decision of the New Active Ingredient Bicyclopyrone An Herbicide for Use on Corn and Establishment of Tolerances for Corn (field, pop, and sweet) and Imported SugarcaneS umm ary This d oc um ent announces that th e U.S. Env ironm enta l Prot ect io n Agency (E PA) h as completed it s evaluation of the new herbicide bicyclopyrone a nd has concluded that it meets the re gulatory stan d ard under the Federal Insecticide, Fung icide , and R odent icide Act (F IFRA ). Five products will b e reg i stered under Section 3(c)(7)(C) ofFIFRA: one te c hnical product, tw o m a nufac turin g use products ( Bi cyc lopyrone Wet P aste M anufacturing Use Product a nd Bic yc lopyrone Wet Paste II Man uf acturi n g Use Product) , and two end-use products (SYN-A l 6003 Herbicide and Ac uronTM Herbicide). The product Acuro nTM will co ntain 0.65% bicyclopyrone, 2.60% m eso tri one, 10.93 % a trazin e, a nd 23.40% S -me to lac hlor. The product SYN -A 1 6003 will co ntain 18.5% bicyclopy rone. T h e labels specify that bicyclopyrone i s gene rally to be applied o n ce annually as a pre-emergent application to corn; however , a split app lic ation for pre e m e r ge nt and ear ly post-emergent i s a ll owed, prov id e d th e m axim um s in g le and an nual app lic at ion rates a r c n ot exceeded. I dentical rat es a nd use patterns apply to both end u se products. l n acco rd a nc e with 3(c)(7)(C) of FIFRA the agency has d ete rmined th a t re g iste rin g bicyclopyrone is in the public interest. Acuro nTM can contro l weeds with a sing le pre - e m e r gent app li cation that may not require additional post
- emergent applications. Acuronn 1 will be labeled for difficult to control weeds with a lo we r rate of atraz ine , S-metolac hl o r , and mesotrione; resulting in decreases in th e amou nt of atraz ine that w ill be app li ed to co rn as well as sma ll e r reductions in S -meto lachlo r and mesotrione. AcuronTM's penetrat ion int o the market will result in the reductio n of other Syngenta atrazine products , resulting in a reduction of 3.6 million pounds of atrazine p e r year on acres th at wou ld h ave been trea ted with tho se product s . The agency is requiring Sy n ge nt a to ach i eve this reduction no later than the 2020 grow in g season. Labels have language including surface and grou n d water adv i sories th at stress the potential for runoff management after treatm en t and statem e nt s inte nd ed to preclude leac hin g to grou nd wate r. Language is o n the labe l th a t is intended to keep the pesticide o n the int e nd e d treatment a rea and i nstructs users of applicator responsibilities and spec ifi c techniques to reduce the poss ibilit y of spray drift. Aerial appl ication is prohibited and a 25-foo t downwind buffer is required to avoid drift to n o n-targe t a reas. End u se lab e ls a l so contain g uidanc e an d inf o rmation which will s low the development of resistance to the target weeds. Ba c kg r· o und On September 23 , 20 1 3 , EPA received an application to register products contain in g the new active ingredient, bicyclopyrone (CAS Number 3520 I 0-68-5) , an herbicide fo r use on corn (fie ld , pop, and sweet) from Synge nta C rop Protec ti o n. Synge nta also s ubmitted appl ic a ti ons for simu lt aneous r evievv to the Pest Mana geme nt Regu l atory Agency ( PM RA) of Canada and th e Australian Pesticides and Veterinary Medicines Authority (APYMA). The EPA. PMRA , and A PVM A comb in ed sc ient ifi c and reg ul a to ry expert i se to conduct a joint review. Each count ry ' s team of sc ien ti sts peer-reviewed the primary revi ews of th ei r co unt e rpart s . Whil e co nt i nuin g to consult and coordinate , human health and eco logica l risk assessme nt s we r e developed by each country individually.

2

### Bicyclopyrone i s an h erb i cide for use on corn with th e estab li s hm ent of t o l

eran ces on corn and imported sugarcane. Bicy l copyrone is to be used on corn fo r the se lecti ve co nt act and r es idual control of weeds in field corn , see d co rn , s il age corn , yellow popcorn , and s weet co rn . The maximum s ing l e a nd max imum annual a ppli ca ti o n rates are 0. 04 5 lb ai /acre. One pre-emergent app li cat i on i s all owed, but the labe ls do allow for sp lit applica tion s (one pre-emergent a nd o ne early post-eme r gen t ) as lon g as the maximum s ing l e an d annu al app li ca ti on rates arc not exceeded. The minimum retreatment int e r

va l (RTI) is 14 days; th e pre- harve s t interval ( PHI ), i s 45 days. AcuronTM co nt ain s 0
. 65% bicyclopyrone , 2.60% me sotri one , I0.93% atraz ine , a nd 23.40% S

metolachlor g ivin g the product three different m o des of ac ti ons (MoA). The pr od uc t SYN

A 160 03 conta in s 1 6. 5 % bi cy cl opy r one and on l y o ne MoA. The label fo r Ac uronTM con tains in formatio n on eac h of the three diff erent mode s of actions. The l abe l for SYN -A 16003 contains in fo rm ation on the MoA for bicyclopryone

. Bicyclopyrone and mesotrione are m e mb ers o f th e hydr oxy pheny l pyruvate di oxy ge na sc ( HPPD ) inhibito r class of h erbi cides (Herb icid e Resis tance Act i on Co mmittee ( HRAC ) Group 27) and be lon g to th e triketo ne s ub c la ss of chemi str y. Bicyclopyrone and mesotrione inhibit th e en zyme I-IPPD and block bio sy nthesi s in plants. Atraz in e is a member of the tri az ine family of herbicides (HR AC Gr oup 5 ). Atrazine wo r ks by inhibiting photosynthesis. S-Metol ac hlor is a m e mb e r of the c hlor oacetamide fa mil y of h

e r

bicides ( HR AC Group 15). S

- Metolachlor i s a seed lin g shoot g r owth inhibitor. The max imum s ing l e and maximum tot al annual rates for Ac uro nTM ar e 3 q uart s per acre. When applied at this rate , Acu r onTM will ap pl y 0.045 \ b ai/acre ofb i cyc l o pyr o ne , 0.18\b ai /acre of mesotrione , 0. 75 lb ai /acre of atraz ine, and 1.605 l b ai/ac r c of S -m etolachlor per sing l e app lication and total per y ea r. The maximum total an nu al rates on co rn , allowed by the age n cy , for meso trione is 0.24 lb ai /acre, atraz in e is 2.5 lb ai /acre, a nd S -met o lac hl or i s 3.7 1 lb ai /acre . The maximum s ing l e a nd maximum total annual rate s for AcuronTM ar e below the maximum use r ates allowe d by the age nc y for me so tri o ne , atrazine , a nd S -m eto lach l or. Eva lu a tion 

### In evaluating a pesticide r eg i st ration app lication , the EPA assesses a w id e varie t y of exposure information (i.e., 

### where a nd h ow th e pesticide is used) and environmental fate (i.e
. , 

### how the chemical will mov e in the env ironment) and toxicity studi es (i.e., 

### e ffe cts on humans and other non-target organ isms) to detem1ine th e like lihood of adve rse effec ts ( i.e . , 

### ri sk) from exposure s as so ciated with the proposed u se of the pr odu ct. Risk assessments are deve l oped to eva luate the environmental fat e of th e compound as well as h ow it might affect a wide range of non-target o r gani s m s including hum an s, terre s trial a nd aq u atic w ildlife and plants. On th e ba s is of these assessments , EP A evaluates and app r oves l anguage for each pesticide label to ensure th e dir ect i o n s for use and safet y m eas ures ar e appropriate to mitigate any potential risk. The pe st i cide 's labe l h el ps to communicate esse ntial limitation s and mitigation s that are nece ssary f o r public safety. It 

### is a v i o lation of federa l law to use a pesticide in a way that conflicts with the labe l.

3Assess m e nt of Ri s k to Hum a n H ea lth 

### EPA r e quire s a wide ra nge of s tudies in order t o assess a pesticide. Both b icyc lopyrone (active in g r edient specific) and AcuronTM (mixture s pe c ifi c) fa ll in the lo wes t ac u te toxic ity categor y of IV via the eye, ora l , de rm a l, and inhalation rout es . The labelin g precautionary s ig n al word i s "CAUT IO N" for all products. Atraz ine also sh ows low acute toxicity data. The acute toxicity ef f ects are s imil ar and do no t indicate a sy ner gist ic effect for atrazine and bicyclopryone for mammals. The table below s ummari zes the toxicological endpoints used in the human health ri sk assess m ent: S ummary of T ox ic o l ogica l Doses a nd Endpo int s for Bic yc lopyro n e f or Use in Hum an H ea lth Risk Assess m e nt s. RfD , PAD, Ex p os ur e / POD Uncert a inty / FQJ> LOC for St ud y a nd T oxico logica l Effects Sc enario A Sa f ety Factor s Ri s k A

ssess ment Acute Dietary (Genera l No endpoint attributable to a single dose and appropriate for the U.S. gene ral population was Population , including seen in the bicyclopyrone toxicological database; therefore , an acute dietary poin t of departure Infant s and for th e ge neral U.S. population was not established. Children) UFA = lOX Acu t e RID = Pren a t a l D eve lo pm e ntal S tud y (New Acute Dietary LOAEL 

### = 

### ur-11 = 1ox 0.0 1 Zea land White rabbit s) (Fe male s 13- 1 0 FQPA SF / UFL = m g/kg/ day Developme nt a l LOAEL = I0 m g/k g bw 49 years of based on ske leta l variations (the age) mg/kg/day lOX aPAD = 0.01 appearance of the 27'h presacral mglkglday vertebrae)
. Carcinogenic ity ( r at) LOAEL = 0
. 28 /0.35 mg/kg/day (M / F) UFA = lOX Chronic RID based on a dose dependent increase in th e Chronic LOAEL = UFH = l OX = 0.00028 incidence of opaque eyes and com eat Die tary (/\ II 0.28 FQPA SF / UFt= m g/kglday damage in both sexes co mp a red to Populations) mg/k g/

day l OX cPAD = contro l s, an in creased incidence of th yro id 0.00028 follicular h ype rpla s ia in male s, a nd a n mg/k g/day increase d incidence of c hronic progressive nephropathy in the kidneys of males. Dermal Short- LOAEL = Pre nata l D eve l opmental S tud y (N ew ( 1-30 days) 10 UF A=lOX Occupational Zeala n d W hit e rabbi ts) and Developmen tal LOAEL = I0 mg/kg bw Int erm ediate

- mg/kg/day UFII = lOX LOC for based on ske letal variations (the Term (1-6 OAF = Uh = lOX MOE = 1000 appearance of the 27'h presacral months) 20.44% vertebrae)
. Inh a lation Pr e n atal D eve lo pm e ntal S tud y (New S ho r 1- ( 1-30 LOAEL 

### = UF A= lOX Occ up a tion a l Zea l and Whit e rabbits) days) an d 1 0 Developme nt a l LOAEL 

### = I0 mg/kg bw I ntcrmediate- mg/kg/day UFII = lOX LOC for based on skeletal variat io ns (the Term (1-6 UFL = lOX MO E= 1000 appearance of the 27'h presacral m

onths) vertebrae).

4S ummar y of Toxicologica l D oses and Endp oi nt s for Bicyc l opyr o ne for Use in Human Health Ri sk Assessme nt s. RfD, PAD , Ex po s ure / POD Unccrta in ty/FQP LO C f o r St udy and T ox ic o l ogica l E ff ec ts Scena r io A Sa f e t

y Fact o r s Ri sk Assessmen t Classi fie at ion: "Suggestive evidence of cancer" based on the presence of rare ocu l ar tumors in Cancer (ora l, male rats
. Quantification of bicyclopyrone's carcinogenic potential is not required. The Cancer dem1al, Assessment Review Committee (CARC) r ecommended using a non-linear approach (i.e., RfD) inhalation) th at will adequately account for all chronic toxicity, including carc ino gen icity that could r es ult from exposure to bicyclopyrone. Point of departure (POD)= A data point or an estimated point that is derived from observed dose-response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. LOAEL = lowest-observed adverse-effect lev e l. UF = uncertainty factor. UFA = extrapolation !Tom animal to human (interspecies). UFH = potential variation in sensitivity among members of the human population ( intr aspec i es). UFL = use of a LOAEL to extrapolate a NOAEL. FQPA SF = FQPA Safety Factor. PAD = population-adjusted dose (a = acu te, c = chronic). OAF= dermal absorption factor. RfD = reference dose. MOE = Margin of Exposure. LOC ::: Level of Concern. The acute and chronic analyses assumed to lerance-level residue s (acute a nalysi s) or average fie ld trial residues (chronic analysis) , 100% c rop-tr eated (CT), and modeled drinking water est imate s. Since adequate processing studies have been submit1ed, which indicate that residu es do not concentrate in corn or sugarcane commodities, the Dietary Exposure Evaluation Model (DEEM ver. 7 .81 ) default processing fac to rs for these commodit ies were reduced to I. The resulting acute [2. 9% acute population-adjusted dose (aPAD) for females 13

- 49 years old] and ch ronic 

### [ :5 91% chronic populati on-adjusted dose (cPA D); ch ildren (I
- 2 years old) were the most highly exposed subgroup] dietary ri sk estimates are n ot of co nc e rn. The occ upational handler exposu re and risk estimates indicate that the short- and intermediate-term dermal a nd inh a latio n combined margins of exposure (MOEs) are not of concern 

### (i.e., MOE :::: 1000) with baseline attire (i.e., s ingl e la ye r of clothing, no g loves, and no respi rator; all MOEs :::: 1, 700). The occupational pos t
application dermal exposure and ri sk estimates are g reater tha n the leve l of concern of I 000 on the day of app li cation, ranging from I ,800 to 49,000 depending o n c rop and activity. Asse s smen t of Ec o log ica l R isk Bicyclopyrone is a relatively soluble, nonvolatile compound that is stable to hydrolysis and is expec ted to be very highly mobile in soil. Bicyclopyrone photodegrades on surface soil, w ith half-live s ranging f rom 4- to 13-day s. lt is s lightly persistent in ae robic so il , metab o li z ing to multiple organ ic transformation products and carbon dioxide. It is s tabl e in anaerobic so il and anaerobic aquat ic systems , and degrades very slowly in aerobic aquatic systems, with half-lives of 393

- 681 days. Bicyclopyrone photodegrades s low l y in water, with h alf- liv es of II to 75 days. The new active in g redient is not expected to bioaccumulate in aquatic and terrestrial organisms. Bicyc lopyrone may move to groundwater via leaching, and may move to s urfac e water bodies v ia spray drift and runoff of dissolved or sorbed re s idues. Bicyclopyrone is class i fied as slightly to practically non-toxic to freshwater a n d estuar in e/ m ari n e fish (and to aquatic-phase amphibians for which freshwater fish serve as surroga tes ) as well as to f reshwa ter invertebrates , but is moderately toxic to estuar ine / marine invertebrates on an acute

5

### exposu r e basis. C hronic effec ts we r e not observ ed in e ith er the freshwater fish ea rl y lif e stage toxicity test or th e f r eshwater invertebrate full life cycle t est after exposure to bicyclopy rone. No chronic estuarine/marine fish or invertebrate s tudi es were sub mi tted and therefore acute -toch ronic ratios (ACRs) based o n freshwater spec ies were used to estimate chronic tox icity e ndp o int s for estua rin e/marin e an ima ls . Tox icity t o aq u at ic vasc ul ar and non- vasc ular plant s was observed upo n exposure to bicyclopyrone. B icyclopyrone is moderately to practically non-toxic t o bi rd s (and to t e rrestri a l-pha se amp hibian s and r ep tiles for which b irds serve as surr ogates), mamma ls, and to young adult hon ey bees (Apis mellifera) 

### on an acute expos ure basi s . Ri sk quotients (RQs) do not exceed the acu te o r chronic risk le ve l s of concern (LOCs) for both freshwater and es tuarine/ marine fish and invertebrate s or for aquatic-phase amphibians. RQ va lu es were a lso below LOCs fo r acute and chronic ri sk to birds , t errestria l-pha se am phibian s and r eptiles and for acute ri s k to mamm als. Howe ve r, RQ s exceed the LOC fo r chronic risk to mammals ( RQs 

### = I - 2.1 ). Co nsistent with the MoA of bicyclopyro ne as an herbicide , exposure at th e maximum labe led application rates may resu lt in risk to terrestrial and se mi- aquati c dicotyledenous (dicot s) plant s (RQs 

### = 1. 35

- 11.48 )
. RQ va lues exceed the LO C for risk to federally listed threa t e ned or end a n ge r ed ( r efer red to as " li s ted ") dicots for pre - eme rge nt use ( RQs 

## = 1.8

- 9.0) as we ll as for both listed and non-li s ted aquatic vasc ular pl ants. The fo llow ing tables provide a comparison of the tox icity ofbicyc lo py ro ne relat ive to a l tern ativ e compou nd s for th e proposed use on corn. These tables provide a co mp a ri so n of toxicity d a t a o n a chemical -b y - chemical basi s; the tables are sorted wi th the most toxic he rbicid e (base d on endpoint val ues) at the top and the least toxic at the bottom. Only groups of organisms for which LOCs are exceeded for bic yc lop yron e ar e li sted
. Vasc ul ar Aqua ti c P l a n t s

**EC~ d**  NOAECs
C h e m ica l

**EC ~o**  NOAEC ( m g/ L) ( m g / L) Ac e t oc hl or 0.0034 0.000 12 Topramezone 0.0067 0.001 B ic y cl op y ro n c 0.013 0.003 Mesotrione 0.0177 0.0075 S-metolach lor 0.048 0.0084 Atrazinc 0.170 NA 2,4

- D 0.2992 NA Glyphosate 4.9 NA NA : Not

**~'a1lable** T e rr es tri a l Pl a n ts N O AECs a nd EC B

Chcm ica l **EC2s 2~**  NOA EC ( lb s ai/ A) (lb s ai / A) Topramezone 0.0001 2 0.000009 2

M cso trione 0.00023 1 0.0001 1 2,4-D 0.00081 1 0.00047 1 Bi c yc lo p y r o n c 0
. 001 2 0.0002 2

Acetochlor 0.0013 1 0.0006 1

Atrazinc 0.003 1 0.0025 1
6Benefits 1Based on seedl ing eme r ge n ce s tud y 1 Based on the vcgctntive vigor s tud y 0.016 2

M a mmalian Chron i c NOAECs an d N OAEL s J C h e mi ca l NOAELM (1111!/ k!!-bW) Topramezone 0.2* Bicy clop y ronc 2. 15 S-Mctolachlor 15* 2,4-D 16 .6 Atrazine 25 * Mesotrione 71.4 Acetochlor 175 Gl y phosate 500 0.0031 2

N O AEC N ( me./ k!!-diet) 4.0 43* 300 332 * 500 1428* 3500* 10 000 ' The NOAEL and NOAEC arc used t o es tim a te c hr

o n1 c dose -b ased and d1ctal)'· b ased ri sk, re s p ec ti vely, to listed mammals

. • E ndp oin t es tim ated based o n the assump tion that I m gfkg·bw = 20 mgfkg-dict Bicyclopyrone will initially be marketed as a four-active ingredient herbicide product (AcuronTM, also formulated with 2.60% mesotrione , 10.93% atrazine , a nd 23.40% Smetolachlor). AcuronTM can prov ide its mo s t effective weed management with a single preemergent appl i cation that may not require additional post-emergent applicat i o ns . Acu ronTM will be labe l ed for difficult to control weed s with a lower rate ofa traz ine , Sme tolachlo r , and mesotri o ne ; re s ultin g in decreases in the amount of atrazine that wi ll be applied to corn as well as sma ll er reduction s in S-meto lachlor and mesotrione. The agency views these reduction s as an environmental benefit. Because of the uncertainty in fully predicting future g r owers' adoption of AcuronTM and ultimately whether growers will use l ess than labeled rat es ov er time , as is common with the alternatives, the Agency is requiring sub mi ss ion of annual rep o rting on herbicide use impacted by the introduction of Acuron TM

. Sy ngenta will develop a nd implemen t an educational and s tewardship program designed to achieve the pr edicted reductions in herbicide usc on corn. Finally, the agency and Syngen ta will monitor the use of AcuronTM , to ensure that s ignificant r eductions in the use ofatrazine occur. Additi onal mit i gat ion m easu re s would be adopted in the event that they do not. Pub li c Comments On 8/13/14, E PA published a notice of receipt in the Federal Register of an application for registration o f bicyclopyrone and annou nced a public comment period of 30 days. No comments were recei ved

. On 9 / 5/14, the EPA published a notice of filing in the Fede ral Register a nnouncing the rec e ipt of the initial filing of the bicyclopy r one petition by Syngenta under th e Fede ral Foo d , Drug , and Cosmetic Act ( FPDCA ) r eq uesting the es tabli s hment of re g ulations for residues of bicyclopyro ne on various commodities. This publication also a nnounced a public commen t period of 30 days; se ve n comments were rec e ived on the FFO CA notice of filin g. Three of the com m e nt s were relevant to bicyclopyrone , th e other four comments were relevant to o ther actions that were batched together with bicyclopryone in the sa me Federal Re g iste r
7document. The commenters noted that pesticides and bicyclopyronc pose a risk to pollinator s . The agency has determined that bicyclopyrone is moderately to practically non-toxic to young adult honey bees (Apis mellifera) on an acute exposure basis. On 2/11 / 20 15 , the EPA published an additional notice of filing in the Federal Register for the import tolerance on sugarcane petition and no relevant comments were received. The EPA announced the proposed decision of the unconditional registration of bicyclopyrone on 3/ 13115, and held a public comment period for 30 days, closing 4/ 13/15. Forty four submissions were received in response to the public commenting period. Forty one subm i ssions were received from various universities, state corn grower associations, state ag ri-bu siness assoc iations , state farm bureaus , state food processors associations , IR -4 , Syngenta , and the public and were in favor of and supported the registration of bicyclopyrone; noting its benefits of con trollin g hard to co ntrol weeds s uch as cockle burr, ra gweed, etc., help i ng with herbicide resistance management, its ability to be used as part of a one-pass spray system, and reduction of the use of atrazine , S-metolachlor, and mesotrione. Three submissions were in opposition to the agency's proposed decision to register bicyclopyrone and based their concern on the agency not consulting with the U.S
. Fi sh and Wildlife Serv ic e and Nat iona l Marine fisheries Serv ic e under the Endangered Species Act and not having adequate label and use restrictions to protected listed species. One of the submissions in opposition to registration was a mail campaign submission contai nin g 5,558 le tte rs. EPA's r ev iew and responses are s umm arized in a separate response to public comments document and is available in the Docket (Docket ID: EPA-HQ-OPP-20 14- 0 3 55 )
. M i ti gat io n a nd La b e lin g R eq uia·c m e n ts Because of the potential for leaching of bicyclopyrone and its degradates , labels have language including surface and ground water advisories that warn of the potential for runoff after treatment and descriptions of conditions that may be susceptib le to leaching to groundwater. In order to mitigate risks, language is on the label th at is intended to keep the pesticide on the intended treatment area, thereby reducing the potential for exposure to non-target organisms. For exan1ple, the following labe l lan g uage is on th e end-use products, S YN-A 16003 Herbi c id e and AcuronTM Herbicide , which instructs users of applicator responsibilities and specific techniques to reduce the possibility of spray drift: Spray Drift Language SPRAY DRIFT Do not apply when weather conditions may cause drift to nontarget areas. Drift may result in injury to adjacent crops and vegetation. To avoid spray drift , DO NOT apply when wind speed is greater than 

### i'O mph or during periods of temperature inversions. A VO ID ING SPRAY DRIFT AT THE APPLICATION SITE IS THE RESPONSIBILITY OF TIIE APPLICATOR.

8The interaction of equipment and weather related fac tors determine the potential for spray drift. The applicator is responsible for considering all these factors when making a decision. Information on Droplet Size The most effective way to reduce spray drift potential is to apply large droplets. Use on ly nozzles producing medium to ultra-course droplet s. Do not use nozzles producing fine droplets. Controlling Droplet Size Volume

- Use high flow rate nozz les to apply the highest practical spray volume. Nozzles with higher rated flows produce larger droplets. Pressure

- Do not exceed the nozzle manufacturer 's recommended pressures. For many nozzle types, lower pressure produces larger droplets. When higher flow rates are needed, use higher rate nozzles in stead of increasing pressure. Number of Nozzles- Use the minimum number of nozzles that provide uniform coverage . Non

- Target Areas Do not apply this pesticide when this product ma y drift to non-target areas. Application Height Applications must be made at the lowest height above the target area that still provides uniform coverage of th e target. Making applications at the lowest yet effective height reduces exposure of droplets to wind. Wind Drift potential is lowest when wind speeds are I 0 mph or less. Howev e r , many factors , including droplet size, pre ss ure, and equipment type determine drift potential at any given wind speed. Note: Local terrain can influence wind patterns. Leave a 25-foot buffer downwind of the application to avoid drift to non-target areas. Temperature Inv ersions Applications must not occur during a temperature inversion because drift potential is high. Temperature inversions re s trict vertical a ir mixing , which causes small suspended droplets to remain in a concentrated c loud. This cloud can move in unpredictable dir ec tions due to the li ght variable winds common during in versions. Temperature inversions arc characterized by increasing temperatures with altitude and are common on nights with limited cloud cover a nd light to no wind. They begin to form as the sun sets and often continue into the morning. Their presence can be indicated by ground fog; however , if fog is not present , inversions can also be

9identified by th e movement of smoke from a ground source o r an aircraft smoke generator. Smoke that layers and moves laterally in a concentrated cloud (under low wind co nditi o ns) indicates an inversion, while smoke that moves upward and rapidly dissipates, indicates good ve rti cal air mixing. Environmental Hazards Do not apply directly to wate r , or to areas where surface water is present or to int ertidal areas below the mean high wate r mark. Do not contaminate water when disposing of equipment washwater o r rin sate . Ground Water Advisory Bicyclopyrone is known to leach through soil into groundwater under cert a in conditions as a result of label use . This chemical may leach into groundwater if used in areas where soils are permeable, particularly where th e water tab le i s s hall ow. Surface Water Advisory This product has a high potential for reaching surface water v ia runoff for several months o r mo re afte r application. A level, well-maintained vegetative buffer strip between areas to which this product is app li ed and s urface wa t e r feat ures s uch as ponds, s treams, and springs will r ed uce the potential loading of bicyclopyrone from runoff water and sediment. Runoff of this product will be reduced by avoiding appl ications when rainfall or irrigation is expected to occur within 48 hours. Aerial Prohibition Do not apply by air. D ata Req uir e m e nts Data from the acute contact and oral toxicity tests with adult honey bees indicate that bicyclopyrone is practically no n-toxi c to bees on an acute ex po s ure basis. However , at thi s time, there are no data regarding the potential acute and chronic effects of the compound on honey bee larval developmen t and survival or the potential for chronic effects of adult bees. Therefore , EPA is requiring th e subm i ss ion of this inform ati on . This data req uirem e nt is exp la ined f urther below
. 

### A nnu a l Re po rtin g AcuronTM's introduction will result in reduction in the use o f other Syngenta products, res ultin g in a reduction of 3
. 6 million pounds of atrazine per year on acres that would of have been treated with those p roducts. The agency is requiring Syngenta to achieve this reduction no later than the 2020 grow in g season.
10Syngenta wi II provide an annual report to EPA no later than March 31 of each year following AcuronTM's first full launch year (the first full launch year currently is anticipated to be 2016 and

. if so, the first report would be made in March of 20 17). The repo rt wi ll i nclude data on the total application of specific herbicide products to corn grown in the U.S. in the preceding year. In the annual report on the 2018 growing season (provided in March of2019) Syngenta will demonstrate a 1.6 million pound reduction of atrazine used per year. In the annual report on the 2020 growing season (provided in March of2021 ), Syngenta will demonstrate an approximately 3.6 million pound reduct i on of atrazine used per year. In the event that these reductions are not achieved, mitigation measures w ill be undertaken to ensure that atrazine uses are reduced. Int ernational Harm o niza tion There arc no established Mexican or Codex maximum residue limits (MRLs) for residues of bicyclopyrone. Bicyclopyrone is the subject of a global data review by the EPA, PMRA , and APVMA. At this time, the residue definitions and the tolerances and MRLs are harmo nized among the revi ew partners. R egulatory De ci s ion In cooperation with our regulatory partners in Australia and Canada, and considering the assessed risk to human health and the environment, the agency concludes that bicyclopyrone meets the regulatory standard under F IFRA. Therefore, the EPA is granting a conditional registration ofbicyclopyrone under Section 3(c)(7)(C) ofFIFRA. The agency initially proposed to registe r bicyclopyrone as an unconditional registration 3(c)(5). However, due to the data requirement s for bicyclopyrone, concerning bees the agency is registering bicyclopyrone as a conditional registration 3(c)(7)(C). The database submitted to support the assessments of human health ri sk and environmental fate and ecological risk is adequate to support the u se and tolerances. There are no risk estimates of concern for human health. Bicyclopyrone has low potential for acute risk to mammal s, birds, freshwater and estuarine / marine fi s h , freshwater invertebrates , amphibians, reptiles , and adult insects. Bicyclopyrone may pose a risk to non-target terrestrial and aquatic plants, and chronic risk to non-human mammals. Label language as outlined in the " Mitigation and Labe ling Requ irements" section will reduce the risk to these organisms. EPA is requiring acute and chronic studies of bieyclopyronc on honey bee larval development and survival and chronic studies of adult bees to support future, more comprehensi ve pollinator risk assessments for bicyclopyrone. For the proposed usc on corn, any exposure to bicyclopyrone tran sported through the p lant into pollen and/or nectar is expected to be much lower than exposure from direct treatment of the crop , which is addressed in the current ecological ri sk assessment. Additionally, there are no data to suggest that bicyclopyrone' s mode of action as a HPPD inhibitor, which results in oxidative s tress and chlorophyll loss in plant cells, would have a direct adverse effect on honey bee health. Therefore, thi s requirement is consistent with the harmoni ze d Guidance for Assessing Pesticid e Risk s to Bees

II(http:/ / www2.epa.gov/s itc s/ pr od ucti o n / lilcs/ 2 0 I+ 06/documents/ pollinator
_ risk _ass essment_guidance
_ 06

_ 1 9

_ 14.pdf). H oweve r , fo r the use pallern cu rrently proposed , the p o tenti a l for adverse effects to adu lt honey b ees from direct appl icati on i s low and there is suf ficent in fo r mation to support a conditional ri sk -b ene fit d ec i s ion. In accorda nce with 3(c)(7)(C) of FIFRA the agency has determined th a t r eg iste rin g bicyclop y rone i s in the public interest. Acuron T M

can con tr ol weeds with a s ingle pre -eme rgent app licati on that may n ot require additio n a l post-emergent applications. AcuronTM will be la bel ed for difficult to control wee ds with a lower rate of atraz ine , S-metolachlor, a nd m esotrion e; resu ltin g in decreases in the amount of at razin e that will be ap plied to corn as well as sma ll e r red uction s in S-metolachlor and me so tri one. Acu ronTM's penetration into th e m a rket w ill res ult in the reduction of other Syngen t a atra z ine products , r es ultin g in a re duction of 3.6 million pounds of atrazi ne per year on ac res that wou ld ha ve been treated wi th tho se products.
T he agency is registering the following five products: Bic yc lop yrone Technica l • 99.3% Bicyclopyrone • Only for formu la tion into an he rb icid e fo r u sc in field corn , seed corn, si l age com , s weet corn , and ye llow corn. Bicyclopyrone W e t Pa s te Manufacturing Use Product • 94.0% Bi cyclopy ro ne • Only for fo rmul ati o n int o an he rbicid e for use in field co m , seed corn , s il age corn , sw eet co rn , and ye llow co rn. Bi cy clopyrone Wet P aste 11 Manufacturing Use Product • 89.6% Bi cyclopyro ne • Only for fo rmul ati o n into an herbicide fo r use in field corn, seed corn, si lage com, sweet co rn , and ye llow co rn. SYN-A 1 6003 H e rbicid e • 1 8.5% Bi cyclopyro ne • Only for use as a pre - emergent and po s t-emergent herbicide fo r the se lective contact and r es idual co ntrol of broad leaf weeds us e in fi e ld corn , see d corn, s il age corn, sweet co rn , and yellow com. Acuron

### TM Herbicide • 0.65% Bicyclopyrone , 2.60% Mesotri one, I 0.93% Atrazine , and 23.40% S

- Metolac hl or • Only for u se as a pre- e mer ge nt a nd po s t- e mer ge nt herbicide for th e select i ve con t ac t and
residual con tro l of broad leaf weeds use in fi e ld corn, see d corn, si lage corn , sweet co m , a nd ye ll ow corn. In summa ry, bicyclopyrone is comparable to the ot her HPPD inhibitors and as s tate d above , this
ne w active ingr e dient m ee ts the regu la tory s tandard under F IFRA. With th e tetms an d

1 2conditions of registration , the agency expects, and will ensure , that the availability of Acuron TM Herbicide results in r eductions in the amount of atrazine app li ed to corn in the U.S. The risk as s essment s supporting this decision can be found in the regulatory docket (Docket ID: EPA

HQ-OPP-20 14-0355.

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