BIOPESTICIDES REGISTRATION ACTION DOCUMENT



## Optimum® AcreMaxTM B.t. Corn Seed Blends

U.S. Environmental Protection Agency (EPA) Office of Pesticide Programs Biopesticides and Pollution Prevention Division (BPPD)

Updated September, 2010Optimum AcreMax B.t. Corn Seed Blends Page 2 of 23 Biopesticides Registration Action Document



### TABLE OF CONTENTS

I. OVERVIEW.................................................. ERROR! BOOKMARK NOT DEFINED.

II. INSECT RESISTANCE MANAGEM ENT................................................................. 6

III. BENEFI TS ............................................................................................................. 10

IV. REGULATORY RATIONAL E .............................................................................. 12

V. REFERE NCES ....................................................................................................... 19Optimum AcreMax B.t. Corn Seed Blends Page 3 of 23 Biopesticides Registration Action Document

I. OVERVIEW

A. BACKGROUND

On April 30, 2010, EPA conditionally registered th e plant-incorporated protectant products, Optimum® AcreMaxTM 1 (OAM1), a seed bl end of 90% HERCULEX® XTRA and 10% HERCULEX® I, and OAM RW, a seed bl end of 90% HERCULEX® RW and 10% Non- B.t. Corn. These registrations were set to expi re on September 30, 2010. The Agency determined that the use of these pesticide pr oducts is in the public interest and that their use during the limited time of the registration would not cau se any unreasonable a dverse effects on the environment. The registrant for both products is Pioneer Hi-Bred In ternational, Inc. (Pioneer). OAM1 is the first registered B.t. corn product to incorporate a "blended " refuge; i.e., the OAM1 product requires a 10% refuge for corn rootworm, and the corn rootworm refuge seed is sold within the same seed bag as the B.t. corn r ootworm product. (OAM1 al so requires a separate 20% refuge for lepidopteran pests, and that refuge is in the form of a structured refuge that is sold separately).

On October 1, 2009, EPA announced a new policy to provide a more meani ngful opportunity for the public to participate on major registration decisi ons before they occur. According to this new policy, EPA intends to provide a public comment period prior to making a registration decision for, at minimum, the following types of applicati ons: new active ingredients; first food uses; first outdoor uses; first residential uses ; and other actions for which the Agency anticipates that there will be significant public interest.

Consistent with the policy of making regist ration actions more transparent, the proposed amendments to the expiring OAM1 and OAM RW corn products were subject to a 30-day comment period because the Agency believes, given past experiences with PIPs in general, these actions are of significant public interest. Based on all data submitted in support of the expiring OAM1 and OAM RW corn registrations and in c onsideration of the public comments received, the Agency concluded that it is in the best interest of the pub lic and the environment to amend the currently existing OAM1 and OAM RW regi strations by extending the current expiration dates to September 30, 2012. The basis for this d ecision can be found in the risk assessments for the expiring OAM1 and OAM RW, and our respons es to comments on the original OAM1 and OAM RW registrations, all of wh ich are set forth in this Bi opesticides Registration Action Document (BRAD).

In addition to the expiring OAM1 and OAM RW corn products, there are other Bt corn PIPs, expressing different proteins eff ective in controlling various lepi dopteran and coleopteran pests, that were set to expire in 2010, and for which the associated registrants have formally requested an extension to the current expi ration dates. Therefore, with in the same docket (EPA-HQ-OPP2010-0607) as this document, the following info rmation were also available for public

examination:

● Cry1F and Cry1Ab BRAD

 Cry 3Bb1 BRAD

● Cry34/35Ab1 BRAD

● mCry3A BRAD

● Optimum® AcreMaxTM B

. t . Seed Blends BRAD

● Current Registration Terms and Conditions for Bt Corn Registrations Set to Expire inOptimum AcreMax B.t. Corn Seed Blends Page 4 of 23 Biopesticides Registration Action Document

2010

● Proposed Registration Terms and Conditions for Bt Corn Registrations Set to Expire

in 2010

EPA made the decision to amend the regi strations of eighteen (18) expiring Bt corn PIP registrations to extend the expi ration dates. We conducted comprehensive assessments of each of these registrations, considering a ll toxicity and environmental e ffects data, data from insect resistance monitoring, and insect resistance re fuge compliance reports, received and obtained since the last comprehensive evaluati on of these products in 2001. Based upon our comprehensive assessment, we reached significant conclusions regarding the positive environmental impact of Bt corn PIPs, and we took several ac tions to strengthen the insect resistance management requirements to ensure continued success in the prevention of the evolution of resistance in target pests.

Since the commercialization of Bt crops, there have been a signi ficant number of published field studies that, combined with the post-registrati on field studies required to be submitted to the Agency, have demonstrated that non-target i nvertebrates are generally more abundant in Bt

cotton and Bt corn fields than in non-transgenic fields managed with chemical insecticides. Thus, these published and registrant-produced st udies demonstrate th at, not only are the Bt crops not causing any unreasonable adverse effects in the environment, but, arth ropod prevalence and diversity is greater in Bt crop fields.

To strengthen insect resistance management of these corn PIPs and to address reports that compliance with the mandated refuge require ments has been decreasing, EPA is requiring enhanced compliance assurance programs (CAP s), and a phased requirement for seed bag labeling that clearly shows the refuge requireme nts. Also, given the increasing variety of PIP products and combinations, and the differing risk of resistance evolution that the various products represent, we are gran ting registrations for the corn PIP products for different time frames, based on assessments of their likelihood of forestalling the evolution of insect resistance. We are registering differing categories of produc ts for differing time periods to reflect the assessed level of risk of resistance posed by th e various corn PIP products. The scheme that we are following includes registration periods generally of five, eight , and twelve years; with the possibility of a fifteen-year registration period for products that are demonstrated to meet specified criteria. We retain, however, the di scretion to register products for time periods differing from these defaults where circumstan ces warrant. In the cas e of OAM1 and OAM RW, we have extended the registrations for two years.

B. USE PROFILE

Active Ingredients:

Bacillus thuringiensis Cry34Ab1 and Cry35Ab1 proteins and the genetic material necessary for their production (P HP17662 T-DNA) in event DAS-59122-7 corn (OECD Unique Identifier: DAS-59122-7)

Bacillus thuringiensis Cry1F protein and the genetic mate rial (plasmid insert PHI8999A) necessary for its production in corn event DAS-Ø15Ø7-1Optimum AcreMax B.t. Corn Seed Blends Page 5 of 23 Biopesticides Registration Action Document

Trade & Other Names:

HERCULEX® I => Cry1F Corn

HERCULEX® RW (Rootworm) => Cry34/35Ab1 Corn

HERCULEX® XTRA => Cry1F + Cry34/35Ab1 Corn

Optimum® AcreMaxTM 1 (OAM1) => Seed Blend of 90% HERCULEX® XTRA

and 10% HERCULEX® I

OAM RW => Seed Blend of 90% HERCULEX® RW and 10% Non- B.t. Corn

OPP Chemical Codes: 006490 (Cry34/35Ab1 corn) and 006481 (Cry 1F corn)

Type of Pesticide: Plant-Incorporated Protectants (PIPs)

Product Profile:

HERCULEX® I The registration for Cry1F Event TC1507 (Event DAS-01507-1), also known as HERCULEX® I, was first granted by the Agency on Ma y 18, 2001. HERCULEX® I expresses the Cry1F insecticidal crystal protein as well as the PAT (phosphinothrin acetyl transferase) protein, which

confers tolerance to the herbicid al active ingredient glufosinate- ammonium. Cry1F is efficacious against lepidopteran pests, and the primary targ et pest of HERCULEX® I is the European corn borer (ECB, Ostrinia nubilalis ); other target pests are corn earworm (CEW, Helicoverpa zea ), southwestern cornborer (SWCB, Diatrea grandiosella ), fall armyworm (FAW, Spodoptera frugiperda ), western bean cutworm (WBCW, Richia albicosta ), and black cutworm (BCW, Agrotis ipsilon ). The main target pests for which insect resistance management (IRM) requirements apply are ECB, CEW, and SWCB.

HERCULEX® RW The registration for Event DAS-59122-7, also kn own as HERCULEX® RW, was granted by the Agency in August, 2005. HERCULEX® RW expresses B.t. toxins Cry34Ab1 and Cry35Ab1, which are efficacious against coleopteran pests. The primary target pests of HERCULEX® RW

are western corn rootworm and northern corn rootworm (CRW, Diabrotica species). Maize containing Event 59122-7 has been modified to expr ess the PAT protein, wh ich confers tolerance to gluphosinate-alum inum herbicide.

HERCULEX® XTRA The registration for HERCULEX® XTRA (E vent TC1507 x DAS59122-7) was granted in

October 2005. HERCULEX® XTRA is the resu lt of a conventional breeding cross between

HERCULEX® I and HERCULEX® RW and is consider ed a stacked PIP because it targets two different kinds of pests (Lepi doptera and Coleoptera) and cont ains two separate PIP active ingredients.

OAM1: EPA File Symbol 29964-6 In February, 2008, Pioneer Hi-Bred International, Inc. submitted an application to register Optimum® AcreMaxTM 1 Insect Protection, a new blended seed product that contains twoOptimum AcreMax B.t. Corn Seed Blends Page 6 of 23 Biopesticides Registration Action Document

different kinds of seeds of the already registered products HERCULEX® XTRA and HERCULEX® I. The new product incorporates th e CRW refuge into the seed bag. The seed blend percentage was amended to 90% HERCULEX® XTRA and 10% HERCULEX® I.

OAM RW: EPA File Symbol 29964-10 In November 2009, Pioneer Hi-Bred International, Inc. submitted an application to register Optimum® AcreMaxTM RW Insect Protection, a seed blend consisting of 90% HERCULEX®

RW and 10% non- B.t. Corn. The new product incorporates the CRW refuge into the seed bag and also can serve as a refuge for the Cry1F portion of OAM1.

Pioneer’s Projected Use in 2010, 2011, and 2012

Pioneer’s forecast for OAM1 U.S. acreage in the 2010, 2011, and 2012 growing seasons is listed below. Pioneer states that “[t]hese estimates ha ve been divided into high-pressure areas for corn rootworm (i.e., the Red Zone) and non-Red Zone acres (i.e., the remaining U.S. corn acreage outside the Red Zone). The Red Zone is defi ned by Pioneer as 90 coun ties that have a 100% chance of corn rootworm infestation in any give n year. These counties ar e primarily located in northeastern Illinois, no rthwestern Indiana and, to a lesser extent, southeastern Wisconsin and southwestern Michigan. Because of the strong selection pressure present in the Red Zone, it is considered a potential area for corn rootworm re sistance to develop. Th e percentages are based on general USDA acreage projections, which project a total of 90 million corn acres in the U.S. in 2010, 2011, and 2012.”

Growing season Red Zone geogr aphy Non-Red Zone geography

2010 ~0.077% ~0.042%

2011 ~5.8% ~8.2%

2012 ~8% ~12%

Pioneer provided information to EPA indicatin g that the total OAM1 acres planted in 2010 was 34,804, which is less than originally projected. (Rood 2010). Pioneer has not changed the initial projections for 2011 and 2012.

II. INSECT RESISTANCE MANAGEMENT

FIFRA Scientific Advisory Panel (SAP)

Pioneer/Dupont's initial registra tion application for OAM1 consis ted of a seed blend of 95% HERCULEX® XTRA and 5% [3.5% (±1.5) ] HERCULEX® I. The HERCULEX® I was intended to serve as the IRM refuge for the corn rootworm active co mponent of HERCULEX® XTRA. The proposed seed blend strategy and re duction in refuge from 20% to 2% to 5% represented a significant paradigm shift for the B.t. IRM strategy that has been employed for over 15 years. BPPD conducted a risk assessment and presented preliminary conclusions to the Scientific Advisory Panel for peer review on February 23 to 24, 2009.

The SAP (2009) expressed concer n about the proposed refuge reduction. The Panel concluded that there was no compelling eviden ce, either in the data provid ed by Pioneer or in the public literature, to support a 5% blende d refuge for this particular pr oduct. The Panel noted, however, that the biology of the corn rootworm makes it su sceptible to successful control and mitigation by a seed blend methodology, if the refuge is of sufficient size.Optimum AcreMax B.t. Corn Seed Blends Page 7 of 23 Biopesticides Registration Action Document

Ad hoc members of the SAP commented on EP A's grant of the OAM1 registration for 2010.

These members noted that the 2009 SAP had voi ced concerns on the simultaneous approval of a blended and reduced refuge for corn rootworm , and stated that EPA "ignored" the 2009 SAP's general conclusion to retain a 20% refuge while research continues. In granting a registration for sale and distribution of OAM1 for the 2010 growi ng season, EPA did consider and rely upon the

advice of the SAP. Pioneer's in itial application sought approval for a 2.5 % blended refuge and

that is what EPA took before the SAP. Concerns raised by the SAP were a major factor in why the Agency did not approve the 2.5% blended refuge proposal. Moreover, the concerns raised by the SAP, and other commenters, are a significant factor in certain of the unique terms and conditions that EPA is placing on the OAM1 re gistration for 2011 – 2012. The ad hoc members also commented that the SAP's concerns rega rding Pioneer's hypothesi s concerning mode of

action were not addressed. EPA did not specifically address the SAP's recommendation on the mode of action hypothesis because that hypothesis did not play a role in our decision. EPA similarly has concerns as to the validity of th e mode of action hypothesis and did not in any way factor this hypothesis in our decision.

Current Submissions

OAM1 is a blended seed product that cont ains 90% HERCULEX® XTRA seeds (Cry34/35Ab1 x Cry1F) and 10% HERCULEX® I seeds (Cry1F).

OAM RW is a blended seed product that contains 90% HERCULEX® RW seeds (Cry34/35Ab1) and 10% non- B.t. Corn.

Seed Blending

Pioneer submitted information and analyses suppor ting their claim that refuge plants will be randomly distributed throughout th e field, including information i ndicating that the expected error of mixing the refuge seed is ±1.5% (usi ng the seed mixing technology described in their submission) and that the standard deviation for planting the correct pe rcentage of refuge is ±1%.

IRM Modeling

EPA Model Description

EPA'S POPGEN (Population Genetics ) simulation models are a series of generalized, flexible population genetics modeling systems modeling th e evolution of resistance to conventional pesticides and transgenic crops. The programs are capable of simulating complex landscapes that vary spatially as well as temporally over the course of a growing season.

POPGEN-D

The deterministic model POPGEN-D is a relatively simple frequency-based model that incorporates non-compliance estimates, non-rand om mating in refuge fields, and larval movement. The model permits modeling of bot h block refuges and blended seed-mixture refuges.Optimum AcreMax B.t. Corn Seed Blends Page 8 of 23 Biopesticides Registration Action Document

POPGEN-S2

The stochastic model POPGEN-S2 is a modification of an earlier stochastic, spatially explicit, dual locus, simulation model designed to evaluate the development of resistance in crop pests to insecticides. (Caprio et al 2006).

POPGEN-SM

The stochastic model POPGEN-SM is a modification of an earlier stochas tic, spatially explicit, dual locus, simulation model designed to evaluate development of resistance in crop pests to insecticides and incorporating multi loci. (Caprio et al 2006).

To incorporate uncertainty in the parameters used in the deterministic model, distributions, based

on data for the lowest and maxi mum possible values, were devel oped as well as a most likely

value. These values were used in PERT distribu tions based on a beta distribution with the most likely value weighted by 4 (Vose 2001).

Dr. David Onstad of the University of Illinoi s commented that it was difficult to understand EPA's modeling because insufficient detail on th e design and inputs was included in the docket for the initial registration. We recognized th at it would have been useful to place more information on the modeling in the docket. Unfo rtunately, this information was not ready for release at the start of the comment period. We supplemented the docket with additional information on the model and model inputs dur ing the comment period. Dr. Onstad also suggested that EPA's modeling efforts should be more transp arent and should include more explicit explanation of how the modeling wa s conducted. We hope that the additional information provided to the docket addressed the concerns regarding tran sparency. Also, EPA will convene a public meeting of the SAP to evalua te these models in early December. We urge all interested parties to partic ipate and submit comments at that time. Additional information on this meeting of the SAP will be availa ble within the normal time frame.

5% Seed Blend

Subsequent to the February 2009, FIFRA Scientif ic Advisory Panel meeting, Pioneer submitted revised modeling that incorporat ed new corn rootworm movement data. EPA fully evaluated this modeling, including assessing the new corn rootworm movement data. In addition, using the

POPGEN model deve loped by EPA ORD, EPA conducted an independent modeling analysis of Pioneer's proposed seed blend using both determin istic and stochastic models. EPA concluded that a number of critical input parameters to the Pioneer modeling were not supported by data or were inadequate to support a rational basis fo r regulatory decisionmaking. Therefore, BPPD

concluded that the results of the Pioneer modeli ng indicating that the propos ed 5% seed blend is superior to a 20% block refuge deployment strategy for OAM1 and corn rootworm were not scientifically supported.

EPA had concerns regarding Pioneer's assumptions about short range insect dispersal because the data (Nowatzki et al. 2003) were limited, a nd were derived from only one location in the

cornbelt. This was a critical factor because the adult insect dispersal input is a sensitive parameter for modeling the durability of block ref uges. Parameter inputs representing a shorter dispersal range lowered the resulting effectiv eness of a block refuge. Using a range of representative parameter values and assumptions to predict the durability of a 20% block refugeOptimum AcreMax B.t. Corn Seed Blends Page 9 of 23 Biopesticides Registration Action Document

versus Pioneer's proposed 5% blended refuge, EPA's deterministic modeling showed that the predicted durability for the 20% block refuge wa s superior to a 5% seed blend strategy (11.95 years vs. 8.1 years).

In addition to the 5% seed blend, EPA modeled other blend percentages for comparison. A 10% seed blend was predicted to have a durability of 11.3 years, which was slightly less durable (5.4%) relative to a 20% block refuge based on EPA's assumptions. EPA concluded, however,

that these results were of lim ited actual utility because a numbe r of parameter inputs to the original Pioneer model did not reflect actual vari ability and/or uncertainty. Therefore, to assess the current application for a 10% blended refuge, EPA conducte d modeling using a range of representative input parameters.

10% Seed Blend

In the latest modeling, EPA incorporated uncer tainty by using probabilis tic distributions of

critical data that we determin ed to be variable and/or uncer tain. The distributions were developed based on acceptable data for the mi nimum, maximum, and most likely, possible values. These values were developed as PERT distributions. Each model was run 2,000 times, and each run utilized input parameters drawn fr om the PERT distributions. "Resistance" was

defined as the resistance allele exceed ing 50%, and EPA measured the mean, 25 th, and 75 th
percentiles of the time to "resis tance." EPA also determined th e proportion of simulations where the time to resistance exceeded 11 years. (The SAP has advised that 15 years with no resistance is a reasonable goal for an IRM program appli cable to a single-gene toxin. The Cry34/35 transgenic toxin has been in use for four years. Therefore, we believe it relevant to assess how many of the model runs indicate that either the 20% block or the 10% blend will delay development of resistance for 11 or more years.) The data from these model simulations indicate comparative durability values of 11.3 years for the 10% blended refuge and 20.2 years for the 20% block refuge. Thus, the 10% blend was 45% less durable than the 20% block refuge currently required for single trait CRW PIPs.

IRM Refuge Compliance

Critical to an assessment of the likely efficacy of an IRM mitigation program is the level of compliance with that program. Data receiv ed by EPA from the Agri cultural Biotechnology Stewardship Technical Committee (ABSTC) indicat e that compliance with the paradigmatic 20% block refuge requirement for most B.t. corn crops has been stead ily decreasing. As noted by a number of commenters, this decreased co mpliance increases the risk of resistance development (see, e.g., Complacency on the Farm , CSPI 2009, and Impact of Genetically Engineered Crops on Farm Sustain ability in the United States, NAS 2010 )

.

For the 2002 to 2008 planting seasons, ABSTC reported refuge compliance either as ‘all compliant' (i.e., always planting a 20% refuge, with in the proper distance) or 'out-of-compliance’ (i.e., not having either a 20% ref uge, or having the refuge not lo cated exactly where required, or neither). In 2007 and 2008, ABSTC be gan to also report if growers at least planted a 15% refuge or/and if most of a grower's B.t. fields met the refuge distance requirement. (Reporting these

additional data reflects that ther e may be degrees of noncompliance, for example, a grower may be inadvertently out of compliance with di stance requirements by a degree that does not materially affect the efficacy of the refuge. Also, while, admittedly, a 15% refuge is notOptimum AcreMax B.t. Corn S eed Blends Page 10 of 23 Biopesticides Registration Action Document

compliant with a 20% refuge requi rement, it has a much different field impact than does a 0% refuge.)

The graphs below compare "out of compliance" versus "almost compliant" data. The upper graph is adjusted for ‘almost compliant’ grow ers in 2007 to 2008; the lower graph is the compiled out-of-compliance data from the ABST C for 2007 and 2008. These data indicate that the unadjusted "out-of-compliance" values may not accurately reflect the actual impact of growers who are, technically, not compliant with the refuge require ments. Therefore, it may be that the "out of compliance" numbers reported r ecently may indicate a greater degree of risk of resistance developing than is actually the case.

ECB CRW ECB/CRW Stacks

2002 86

2003 92

2004 91

2005 92 93

2006 89 89 78

2007 89 86 82

2008 86 84 81

ECB CRW ECB/CRW Stacks

2002 86

2003 92

2004 91

2005 92 93

2006 89 89 78

2007 80 80 70

2008 78 74 72 Compliance with Re fuge Requirements

(20% from 2002-2006; > 15% refuge planted; info only available for 2007/2008)

65 70 75 80 85 90 95 100

2001 2002 2003 2004 2005 2006 2007 2008 2009

Planting Season% Compliance

ECB CRW ECB/CRW Stacks

Compliance with Refuge Requirements

(20% refuge planted in all years)

65 70 75 80 85 90 95 100

2001 2002 2003 2004 2005 2006 2007 2008 2009

Planting Season% Compliance

ECB CRW ECB/CRW Stacks

III. BENEFITS

We expect OAM1 to have the following benefits: (1) Reduced pesticide use in the refuge. Currently, the 20% block refuge may be sprayed with pesticide to mitigate pest damage. The blended in-field refuge will not be sprayable. (2) Significantly less complicated refuge deployment for the corn rootworm active ingredient. Currently, to be fully compliant with theOptimum AcreMax B.t. Corn S eed Blends Page 11 of 23 Biopesticides Registration Action Document

refuge requirements, growers must accurately ca lculate 20% of the field, accurately determine the proper distance for th e refuge field, and properly plant th e required acreage in the correct location. Moreover, there are temporal concerns , as the refuge field must be planted at, essentially, the same time as the yield field so that emergence of refuge rootworms is contemporaneous with emergence of field root worms. Anecdotal reports from growers make clear that meeting each of thes e requirements can be challenging in the actual on-farm environment. A product with the refuge blended w ith the field seed will ease deployment of the rootworm refuge. (3) Increased grower co mpliance with IRM requirements for the corn rootworm active ingredient. A s eed blend product incorporating an effective refuge in the seed bag would lead to 100% grower compliance for plan ting a refuge. This is a significant benefit, although perhaps not as great as the raw da ta on refuge compliance might suggest.

In addition, indirect benefits of introducing Optimum® Ac reMaxTM 1 may include reduced energy consumption for manufacture, transport, and application of ch emical insecticides; reduced waste streams arising from pesticide ma nufacture; reduced dispos al of pesticide waste containers; and reduced residues fr om pesticide applications.

Efficacy and Yield Benefits

Pioneer conducted a two year study (2006 to 2007) to assess efficacy and yield benefits of a blended seed refuge. The purpose of the study was to determine the effects of a blended refuge approach on field standability, root ratings, and yield (three effects measured at each treatment level). The 2006 experiment was replicated at eight different locations in a randomized block design with four replicates for all five treatmen ts. The treatments were: (1) untreated control; (2) conventional seed treated with P1250; (3) 100% HXRW (HERCULEX® RW) seed treated with P250; (4) 10% seed mix of conventiona l seed treated with P250 and 90% HXRW seed treated with P250; and (5) 20% seed mix of conventional seed treated with P1250 and 80% HXRW seed treated with P250. During July 2006, five roots per plot we re randomly selected, root damaged scored using the Iowa State 0-3 no de injury scoring, and yield determined at end of the growing season. Under low insect pressure, Pioneer reports little difference in node injury or yields between treatments (no data provi ded). Under high ins ect pressure, all HXRW treatments had approximately equal grain yiel d and node injury and the 10% and 20% seed blends were equivalent to th e control of 100% HXRW maize.

The Center for Science in the Publ ic Interest (CSPI) commented thatour analysis of the benefits

of OAM1 should consider overall IR M compliance, including that in the lepidopteran refuge. In addition, CSPI stated that EPA should require ad ditional conditions related to the lepidopteran refuge, such as requiring that refuge requirements be placed on seed bags, requiring that on-farm assessments be conducted by third parties, requir ing growers to certify compliance annually, and separating compliance data into geographic regi ons. EPA agrees with and is implementing a number of these suggestions. Pioneer has comm itted to including labe ling on OAM1 seed bags indicating the size of the required refuge for lepidoptera, and this is being made a specific term of the registration. (We note that this is also bei ng made a term of all B.t. corn registrations and that all B.t. corn registrants ar e required to make best efforts to implement this change on as many bags of seed as possible for the 2011 grow ing season, on 50% of seed bags for the 2012 growing season, and on 100% of seed bags for th e 2013 growing season). EPA is also requiring that on-farm assessments for all B.t. corn regi strations must be conducted by independent, thirdparties. Also, compliance data will be require d to be submitted in a form that will permitOptimum AcreMax B.t. Corn S eed Blends Page 12 of 23 Biopesticides Registration Action Document

evaluation by geographic region. We are not, at th is time, requiring that gr owers annually certify ex post facto that they complied with the IRM requiremen ts; but, that is a requirement that we will consider in the future, should the compliance picture not improve.

Dow AgroSciences commented that the requirement for a separate structured lepidopteran refuge would create confusion among growers. We agr ee that there is the possibility of grower

confusion related to the fact th at there must be two separate refuges for OAM1. Pioneer is required to conduct enhanced grower education to ensure that purchasers of OAM1 understand the lepidopteran refuge requirements. Pioneer also is responsible for 2000 independent, thirdparty on-farm assessments to address compliance with the lepidopteran refuge requirements. Significant non-compliance with the OAM1 lepidopteran refuge requirements, if verified, could have implications for continued availability of OAM1 in 2011 and beyond .

In 2007, the study was repeated with the additi on of HX1 (HERCULEX® I) as refuge seed (treated with P250 and P1250). BPPD did not se e statistically significan t differences between node injury, % root lodging, a nd grain yields between any of the HXX (HERCULEX® XTRA) treatments except with respect to no de for the 20% refuge with P250.

IV. REGULATORY RATIONALE

A. 2010 Registration Decision

Section 3(c)(7)(A) of FIFRA provides for the regist ration or amendment of a pesticide when the pesticide and proposed use “...are identical or substantially simila r to any currently registered pesticide and use thereof, or differ only in ways that would not significantly increase the risk of

unreasonable adverse effects on the environmen t, and (ii) approving the registration or amendment in the manner proposed by the applicant would not significantly increase the risk of any unreasonable adverse effect on the environment.” Unreasonable adverse effects on the environment are defined under Section 2(bb) of FI FRA as “... any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide...” Thus, pursuant to Section 3(c)(7)(A), EPA may conditionally register a pesticide if (1) the pesticide and its proposed use are identical or substantially similar to a currently registered pesticide; or (2) the pesticide and its proposed use differ only in ways that would not significantly increa se the risk of unreasonable a dverse effects; and (3) approving the registration would not significantly increase the risk of any unreasonable adverse effect.

In our registration decision for the 2010 grow ing season, we found that OAM1 and OAM RW met criteria (2) and (3) of Section 3(c)(7)(A) fo r a time-limited registration to expire September 30, 2010. Optimum Acre Max (OAM) 1 is a seed bl end consisting of two currently registered products, 90% Herculex Xtra and 10% Herculex I. Optimum Acre Max (OAM) RW is a seed blend consisting of an already registered produ ct and non-PIP corn, 90% Herculex RW and 10% non-B.t. corn. Thus, both products were found to be substantially similar to already registered PIPs in composition and use site (field corn). These products did not meet criteria (1), however, because the proposed use of OAM1 and OAM RW that achieves the insect resistance management refuge via a seed mix rather than a block refuge is not substantially similar to any currently registered pesticide. Having the re fuge in the bag of seeds is a novel approach.

We determined, however, that each of these pr oducts met criteria (2) as, when used in

accordance with the terms and conditions of the tim e-limited registration set to expire SeptemberOptimum AcreMax B.t. Corn S eed Blends Page 13 of 23 Biopesticides Registration Action Document

30, 2010, neither would significantly increase the risk of unreas onable adverse effects on the

environment. Since OAM1 and OAM RW are substant ially similar to already registered PIPs in composition and use site, EPA’s considerati on of whether these new products would significantly increase the risk of any unreasonable adverse effect on the environment was limited to the change in insect resistance management refuge deployment and percentage, i.e., a 10% seed blend in the bag versus a 20% block refuge . The unreasonable adverse effect of concern was the development of resistance to Cry34/35Ab1 in corn. Thus, we considered: (1) how does the registration of OAM1 and OAM RW contribut e to the development of corn rootworm resistance to Cry34/35Ab1 corn; (2) should this re sistance develop, what risk does it pose to man or the environment; and (3) taking into account the economic, social, and environmental costs and benefits, does this risk constitu te an unreasonable adverse effect?

The Risk of OAM1 and OAM RW Registrati ons Causing CRW Resistance to Cry34/35Ab1

The modeling used by EPA to assess IRM strategi es utilizes comparative simulation models. The model durability output, years to resistance, is intended to be used for comparative purposes to evaluate different refuge options on a relative basis. The durability outputs that EPA determined for the proposed 90% CRW protected seed/10% non-CRW protected seed blend, and a 20% block refuge are 11.3 years to resistance, and 20.2 years to resistance, resp ectively. Thus, our analysis indicated that, as modeled, the proposed seed blend is 45% less durable on a comparative basis than the 20% block refuge cu rrently required for si ngle trait CRW PIPs .

Besides the currently registered Pioneer PIPs, Cry34/35Ab1 corn is registered in a number of

other B.t. corn PIPs, including multi-CRW B.t. toxin products, by Monsanto and Dow AgroSciences. Should resistance develop to Cry34/35 in a OAM1 seed blend, these other products could be adversely affected including po tential loss of efficacy and viability as CRW control tools. We note, in particular, the re cent statement of the National Research Council to

the effect that “.

. . results from simulation models and small-scale laboratory experiments

indicate that the evolu tion of resistance to two- toxin cultivars is accelerated when plants that produce two B.t. toxins are grown near plan ts that produce just one to xin.” National Academy of Sciences, Impact of Genetically Engineer ed Crops on Farm Sustainability in the United States, 2-37 (2010). Based on our assessment, we concl uded that significant acreage of a 10% seed blend with a single, non-high dose mode of actio n such as Cry 34/35Ab1 likely increases the risk

of resistance for all B.t. corn products containing Cry34/ 35Ab1. But, the time-limited registration expiring September 30, 2010, likely would not increase the risk of resistance to Cry34/35Ab1.

Pioneer projected that the tim e-limited registrations granted for the 2010 growing season would result in planting on only approximately 0.042% of acres of non-Red Zone geography corn acres; and only on approximately 0.077% of Red-Zone ge ography corn acres. In the context of 90 million acres of corn planted in the United States annually, we concluded that plantings on such limited acreage would not have effects on CRW resistance development.

The ad hoc members of the SAP commented that the evolution of resistance that occurs as a result of OAM1 presence in the field will speed resistance to Cry34/35 pyramided products. Comments from Dow Agrosciences and Syngent a also expressed concern that OAM1 would impact other PIP products and speed resistance evolution. CSPI commented that if the registration decision was based in part on sales projections, then ac reage caps should be a term of the registration. We appreciat e the concerns of the ad hoc members of the SAP, DowOptimum AcreMax B.t. Corn S eed Blends Page 14 of 23 Biopesticides Registration Action Document

Agrosciences, and Syngenta regarding the poten tial of OAM1 to accele rate evolution of resistance to Cry 34/35. This is a concern that we share. We took steps and imposed terms on the OAM1 registration for the 2010 growing season to address these concerns. Pioneer was required to implement an enhanced resistan ce monitoring plan for OAM1 that included benchmark studies showing susceptibility of th e western corn rootworm populations (WCRW) in the Sublethal Seedling Assay. These studies must be submitted by December 1, 2010. Pioneer must attempt to obtain benchmark susceptibility data using the Subletha l Seedling Assay for the northern corn rootworm as well, and submit such studies by December 1, 2011. Pioneer must also submit by December 1, 2010, a detailed OAM1-sp ecific resistance monitoring and remedial action plan, including an analysis to determine the expected fi eld performance criteria for OAM1 products so that unexpected damage can be benchmarked. This plan will be updated by December 1, 2012, if needed, based on continue d field evaluation of OAM1 performance. Pioneer was also required to develop programs to evaluate whether there are statistically significant and biologically releva nt changes in target insect susceptibility to Cry1F and Cry34Ab1/Cry35Ab1 proteins in the targ et insects; and a remedial ac tion plan that must set forth the specific measures Pioneer will take in the event that any field-relevant insect resistance is

detected. While we are not re quiring specific acreage caps as part of the registration for 2011 and 2012, we will closely monitor the extent of sales and plantings of OAM1, as well as all insect monitoring data. In the event there is a ny indication of resistance evolution, Pioneer must report that to EPA immediately. We will assess all data and information relevant to the indication of resistance evolution and, if we de termine that such action is appropriate, will use our authority under Section 6(c) of FIFRA to suspend the registration.

Should Resistance Develop, What Risk Does it Pose to Man or the Environment, and What Economic and Social Costs?

Should Cry34/35Ab1 resistance develop, there would be an increase in conventional chemical insecticide use for U.S. corn production. Although there are other CRW controlling PIPs in the marketplace and under development, Cry34/35Ab1 resistance would not only impact OAM1 and OAM RW, but also HERCULEX® RW, HERCU LEX® XTRA, and GenuityTM SmartStaxTM.

Increased use of conventional insecticides woul d increase impacts on the environment and man. There would also be indirect impacts in in creased energy consumption for manufacture, transport, and application of chemical insect icides; increased waste streams arising from pesticide manufacture; and increase d disposal of pesticide waste containers and residues from pesticide applications.

What are the Economic, Social, and Environmental Benefits of OAM1 and OAM RW?

Both OAM1 and OAM RW have been determined by EPA to be efficacious in their control of

corn rootworm.

OAM1 and OAM RW should increase grower co mpliance with CRW refuge requirements by providing a novel and effective way of simplifying the refuge deployment process for growers as the corn rootworm refuge is deployed as a seed bl end rather than a separate block in the field.

OAM1 and OAM RW should also reduce the insect icide use in the CRW refuge and in the CRW-PIP fields. Currently, corn rootworm PIP products require in secticide treatment of the PIP acreage, even if economic thresholds are not reache d. This use of insectic ides solely to support the management of resistance has b een required if aerial insecticides are applied to the refuge for control of CRW adults or if pests other than a dult corn rootworms are treated with CRW-labeledOptimum AcreMax B.t. Corn S eed Blends Page 15 of 23 Biopesticides Registration Action Document

insecticide on the refuge acres when adult corn rootworms are present. OAM1 and OAM RW

would reduce this IRM based use of insecticides. Indirect benef its of decreased insecticide use include reduced energy consumption for manufactu re, transport, and application of chemical insecticides; reduced waste streams arising from pesticide manufacture; reduced disposal of pesticide waste containers and residu es from pesticide applications.

OAM1 and OAM RW should benefit growers by simplifying the planting process.

Registration Decision for 2010 Growing Season

We concluded that OAM1 and OAM RW met the cr iteria for registration under FIFRA Section 3(c)(7)(A). Our assessment suppor ted the determination that th ese products are not likely to contribute towards the development of resist ance of CRW to Cry34/35A b1 during the period of the time-limited registration in effect for the 2010 growing season. Our assessment of the likely impacts concerning ease of use, increased grower compliance, efficacy, and reduced insecticide use coupled with our determination that OAM1 and OAM RW are not likely to increase the risk

of resistance of CRW to Cr y34/35Ab1 developing during the 2010 growing season supported the

conclusion that the criteria under FIFRA Section 3(c)(7)(A) were met such that registration of OAM1 and OAM RW would not pose a risk of unr easonable adverse effects on the environment during this period.

On October 1, 2009, EPA announced a new policy to provide a more meani ngful opportunity for the public to participate on major registration decisi ons before they occur. According to this new policy, EPA intends to provide a public comment period prior to making a registration decision for, at minimum, the following types of applicati ons: new active ingredient s; first food use; first outdoor use; first residential use; and other actions for which the Agency anticipates that there will be significant public interest.

Notwithstanding that the current actions on OAM1 and OAM RW qualify as "actions for which the Agency anticipates that there will be signif icant public interest," EPA believed that it was in the best interests of the public and the envir onment to issue the registrations for OAM1 and OAM RW without delay. The PRIA (Pesticide Registration Im provement Act) deadline date of May 1, 2010, was sufficiently late in the grow ing season that a 30-day delay would have lessened the likelihood that sign ificant acreage of these product s could be planted in 2010. Given the potential benefits attendant to the bl ended refuge concept, EP A concluded that it was in the best interests of the public and the envi ronment to issue the registrations for OAM1 and OAM RW without delay for 2010 gr owing season. The registration is only effective for the current growing season. Therefore, consistent with the Agency’s policy for making certain registration actions more transparent, EPA issued these time-limited registrations with an initial period to expire September 30, 2010, and, concu rrent with their issu ance, provided a 30-day public comment period on the time-limited registrati ons. EPA registered this product as a timelimited registration, with the unde rstanding that public comment s could bring to light new

information or concerns that co uld inform EPA’s initial decisi on. Any subsequent action taken on these registrations will be informed by any information received during the public comment period.

CSPI commented that the public participation process for th e OAM1 registration for the 2010 growing season was inadequate. CSPI believed that the opportunity for public comment shouldOptimum AcreMax B.t. Corn S eed Blends Page 16 of 23 Biopesticides Registration Action Document

have occurred prior to the registration decision. We do not disagree with the comment. All things being equal, however, we felt that it was important to meet the PRIA due date for this action, and that taking public comment concurre nt with the registra tion would not unfairly deprive the public of the opportuni ty for meaningful comment, nor deprive us of the benefit of public input. The OAM1 2010 regi stration was a very short, approximately five-month, time limited registration that was only good for one grow ing season. Moreover, as noted in the April 30, 2010, BRAD, the timing of the registration wa s so late in the growing season that it precluded significant sale and planting of the pr oduct. As it happened, data submitted by Pioneer (Rood, 2010), verified that OAM1 acres for 2010 am ounted to only 39,000 acres, which is less than projected in the earlier BRAD. We are pleased that we di d receive meaningful comment on the April 30, 2010, registration action, and that th at comment has been useful in informing the preliminary decision that we are announcing today. The OAM1 registration that we are proposing today contains a number of enhanced requirements for corn rootworm resistance management that we believe will have a propitio us impact not only on this registration, but on other B.t. corn registrations as well. Fi nally, comments received on the OAM1 registration played a significant role in EPA's delibera tions on the concept of tiered time-limited registrations. As discussed below, we believe that it makes sense to make a specific connection between the risk of resistance evolving that a particular product presents and the time permitted for the registration of that product to be in eff ect. Products that we de termine through scientific evaluation to meet a stringent sta ndard for protecting against the ri sk of resistance evolving will be eligible for a registration of up to fifteen y ears. CSPI also commented that EPA "stealthily" released the OAM1 BRAD, and did not announce the comment period either in the Federal Register or by press release. We can assure all concerne d that the intent was not to be "stealthy." EPA opened the public comment period for this acti on as it has done for all other actions subject to the new public participa tion initiative, i.e., by announc ing the comment period on the Agency's public participation webpage. This co mment points out to us, however, that there are instances where more extensive efforts to publicize the initiation of a comment period and the availability of BRADs, etc., may be warranted. We undertook such efforts in conjunction with the B.t. corn registrations comment period.

B. Registration Decision for 2011 and 2012 Growing Seasons

In the April 30 BRAD, we preliminarily concluded that our modeling analys is combined with the Pioneer sales projections for the 2011 a nd 2012 growing seasons supported continued registration of OAM1 and OAM RW for 2011 and 2012. We noted that Pioneer predicts OAM1 and OAM RW acreage to increase up to 8% of the Red Zone and 12% of the non-Red Zone. EPA invited comments during the 30-day comment period on the preliminary decision to register OAM1 and OAM RW for the 2011-2012 growing seas ons. Important to this preliminary

decision was the fact that Pioneer committed to additional elements that would enhance the IRM plan applicable to OAM1 and OAM RW regardi ng insect resistance monitoring and remedial

action should resistance be detect ed, and the refuge assurance pr ogram. These were listed in

detail in the terms and conditions of th e April 30, 2010, OAM1 and OAM RW registrations.

Section 3(c)(7)(A) of FIFRA provides for the regi stration or amendment of a pesticide when the pesticide and proposed use “...are id entical or substantially simila r to any currently registered pesticide and use thereof, or differ only in ways that would not significantly increase the risk of

unreasonable adverse effects on the environmen t, and (ii) approving the registration or amendment in the manner proposed by the applicant would not significantly increase the risk of any unreasonable adverse effect on the environment.” Unreasonable adverse effects on theOptimum AcreMax B.t. Corn S eed Blends Page 17 of 23 Biopesticides Registration Action Document

environment are defined under section 2(bb) of FI FRA as “... any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide...” Thus, pursuant to section 3(c)(7)(A), EPA may conditionally register a pesticide if (1) the pesticide and its proposed use are identical or substantially similar to a currently registered pesticide; or (2) the pesticide and its proposed use differ only in ways that would not significantly increa se the risk of unreasonable a dverse effects; and (3) approving the registration would not significantly increase the risk of any unreasonable adverse effect.

The Agency concludes that the following Cry34/ 35Ab1 corn product registrations, set to expire September 30, 2010, and described in-depth throu ghout this BRAD, meet both criteria (1) and (2):

(1) Optimum® AcreMaxTM 1 (OAM1) => Seed Blend of 90% HERCULEX® XTRA

and 10% HERCULEX® I

(2) OAM RW => Seed Blend of 90% HERCULEX® RW and 10% Non- B.t. Corn

Each of these Cry34/35Ab1 corn products are identical in both composition and use (field corn) to plant-incorporated protectants that are curre ntly registered. Thus, criterion (1) has been fulfilled. With regard to criterion (2), the Agen cy maintains, as was previously determined for the original registration of thes e particular products, that cu ltivation of Cry34/35Ab1-containing

corn will not cause unreasonable adverse effects on the environment. The conditional environmental effects data, submitted in respons e to terms and conditions of registration and summarized in section II(C)(2)(b) of this BRAD, strengthen the Agency ’s initial position and also confirm that long-term effects on non-targ et organisms are not anticipated. Lastly, the continued use of these products will likely still pr ovide many of the benefits as were evaluated to support the OAM1 registration for the 2010 gr owing season (e.g., reduction in use of conventional insecticides that are highly toxi c to both humans and the environment; increased compliance with CRW refuge requirements).

In conclusion, as the expiring Cry34/35A b1 products (Optimum® AcreMaxTM 1 (OAM1) =>

Seed Blend of 90% HERCULEX® XTRA and 10% HERCULEX® I; and OAM RW => Seed

Blend of 90% HERCULEX® RW and 10% Non- B.t. Corn) have met the required criteria under section 3(c)(7)(A) of FIFRA, the Agency has amended these registrations to extend their respective expiration dates as follows:

Product Name (EPA Reg. No.) Proposed Expiration Date

OAM1 (29964-6) September 30, 2012

OAM1 RW (29964-10) September 30, 2012

Although data provided were satisfactory to make the determinations required by section 3(c)(7)(A) of FIFRA, they we re not sufficient to support an unconditional registration under FIFRA section 3(c)(5). Additional data, specifically in relation to insect resistance management are necessary for a finding of registrability under FIFRA section 3(c)(5) and remain as terms or conditions for the purposes of the proposed amendments.Optimum AcreMax B.t. Corn S eed Blends Page 18 of 23 Biopesticides Registration Action Document

C. Period of Registration

In the 2001 BtCorn reassessment, EPA determined that it was appropriate to amend the thenexisting registrations to extend the period of regi stration of those products to an expiration date of October 15, 2008. All of the products being as sessed at that time were efficacious against lepidopteran pests. EPA based this action on the finding that use of Cry1Ab or Cry1F expressed in corn will not significantly increase the risk of unreasonable adverse effects on the environment “for the limited time period of 7 additional year s (to October 15, 2008).” These registrations were later amended to extend the period of regi stration to an expirati on date of September 30, 2010. EPA subsequently granted time-limited regi strations to products efficacious against coleopteran corn rootworm pests. For exam ple, EPA registered Cry3Bb1 on February 24, 2003, to May 1, 2004, and extended that registration twice, to February 24, 2008, and September 30,

2010.

As set forth elsewhere in this docum ent, EPA’s primary concern for the Bt protected transgenic corn products is the possibility that target pest s will develop resistance to one or more of the plant-incorporated protectant (PIP) t oxins. Development of resistance to a Bt toxin would be a grave adverse effect, and, for over 15 years, EPA has imposed stringent requirements intended to countermand the potential development of resist ance. Registrants similarly have been busily developing various products, product mixes (i.e., so-called “pyramids” and “stacks”), and resistance strategies, to maximize agronomic bene fits and address resistance management issues. The result has been a vast array of product combin ations and, occurring over the past couple of years, a re-emergence of varying ref uge requirements for different products.

As discussed in the 2001 Bt PIP BRAD (at IID13), the earliest Bt corn registrations did not include mandatory refuge requirements. There was a lack of scientific consensus as to what the appropriate refuge requirement should be, a nd, it was assumed that the limited market penetration of these early crops would be so lo w as to guarantee that ad equate natural refuges would be available from neighboring non- Bt corn fields. From 1995 to 1997, Bt corn registrations included voluntary re fuge requirements of 0% to 20% in the Corn Belt. In 1999, the Agricultural Biotechnology Stewardship Technical Committee (ABSTC), in conjunction with the

National Corn Growers Associat ion, proposed uniform insect resistance management (IRM) requirements for Bt corn registrations. With some modificat ions, this proposal, put in place for the 2000 growing season, formed the base line IRM requirements for almost all Bt corn registrations for the better part of a decade: fa rmers were required to plant a 20% refuge that could be treated for insects, or a 50% treated re fuge in cotton-growing ar eas; all refuges to be planted within one-half mile of the Bt corn field.

These uniform requirements brought certainty and consistency to the mark et after the initial period where many Bt corn products had different refuge requirements. Recently, however, as product developers have begun to conceive of products with differe nt combinations of “pyramided” products (i.e., products containing two or more toxins efficacious against the same pest) and “stacked” products (i.e., products combin ing toxins efficacious against different pests), the refuge requirements have begun to vary. For example, certain products require a 20% external refuge; some products permit a 5% ex ternal refuge; one produc t incorporates a 10% seed blend refuge; we have applications in proc ess for products that prop ose to incorporate a 5% seed blend refuge; and other permutations are possible.

Given the profusion of various toxin combinati ons and refuge options, we can no longer proceedOptimum AcreMax B.t. Corn S eed Blends Page 19 of 23 Biopesticides Registration Action Document

on the basis that, as concerns insect resistance management, all products are equal. It was a relatively simple proposition when the default requi rement of a 20% sprayed refuge applied to

almost all of the Bt corn crops in the market. Under thos e circumstances, the relative durability of products against the development of resist ance was functionally equivalent, and, as a consequence, imposing functionally equivalent registra tion periods was appropriate. That is now no longer the case.

As part of our continually evolving regulatory approach to the conti nually evolving product mix wrought by developers, we think it appropriate to revise ou r regulatory requirements in scientifically defensible ways to reflect the co mparative level of risks posed by the products that we regulate. Here, for example, where we’ve determ ined that a particular product, or category of products, likely will pose less risk of insect resi stance developing to a particular PIP protein, we think it appropriate to grant that particular pr oduct, or category of products, a registration for a period greater than that grante d a corresponding product that poses a greater risk of insect resistance developing. This approach is reflective of complementary principles: first, to ensure that we apply our limited resources to the products that pose greater risk of adverse effects to the environment; and, second, to conserve the resources that registrants and applicants must expend in amending the registrations of products that pose less risk of adverse effects to the

environment.

The scheme that we are following includes registration periods of fi ve, eight, and twelve years; a fifteen-year registration period wi ll also be available, if adeq uately supported by our science assessment. In this scheme, (i) a product with a single PIP toxin, and a 20% external refuge, qualifies for a five-year registrati on; (ii) a product with pyramided PIP toxins (i.e., two or more toxins with distinct, non-cross reacting modes of action), that are non-high dose (the definition for a high dose product remains unchanged), with eith er a seed blend or ex ternal refuge, qualifies for an eight-year registration; (i ii) a product with pyramided PIP t oxins (i.e., two or more toxins with distinct, non-cross r eacting modes of action), that are high-dose, with either a seed blend or external refuge, qualifies for a tw elve-year registration; (iv) a pr oduct with pyramided PIP toxins (i.e., two or more toxins with distinct non-cross reacting modes of actions), with either a seed blend or external refuge, that has been determined by EPA’s science assessment to be 150% as durable as the baseline single toxin product with a 20% external refuge, would qualify for a fifteen-year registration. Products determined by EPA’s science asse ssment to be less than 100% as durable as the baseline single toxin product with a 20% external refuge would not qualify for a five-year registration and the regi stration period for such products will be determined on a caseby-case basis consistent with the level of risk they pose. Similarly, instances where other risk issues may arise, or where novel resistance concer ns may be present, would also be determined on a case-by-case basis, as will novel refuge c onfigurations that may present unique durability profiles.

V. REFERENCES

Bailey, L., R. Binning, L. Higgins, D. Langer, R. Layton, S. Lefko, T. Nowatzki, E. Owens, and T. Rood. 2008. Trait Durability Plan for Optimum® AcreMaxTM1 Insect Protection Following Commercialization. Unpublished report submitted to the US EPA (MRID 473567- 09).

Caprio, MA, T Nowatzki, B Siegfried, LJ Mein ke, RJ Wright & LD Chandler. 2006. Assessing theOptimum AcreMax B.t. Corn S eed Blends Page 20 of 23 Biopesticides Registration Action Document

Risk of Resistance to Aerial Applications of Methyl-Parathion in the Western Corn Rootworm. Journal of Economic Entomology, Vol. 99(2): 483-493

Caprio, M. A., D. Sumerford & S. Sims. 2006b. Evaluating transgen ic plants for suitability in pest and resistance management programs, 2nd edition. L. Lacey & H. Kaya [eds]. Field Manual of Techniques for the Applicati on and Evaluation of Entomopathogens.

Coats SA, JA Mutchmor, and JJ Tollefson. 1986. St udy of migratory flight in the western corn rootworm (Coleoptera: Chrysomeldiae). Environmental Entomology, Vol. 15: 620-625

Davis, P. and S. MacIntosh. 2008. Benef its Document of Optimum® AcreMaxTM 1 Insect Protection. Unpublished report subm itted by Pioneer Hi-Breed Intern ational, Inc. to the US EPA (MRID 473567-10).

EPA MRID No. 47339601 Bailey, L. (2008) 2007 Insect Resistance Management Compliance Assurance Program Report for Corn Borer-Protect ed B.t. corn, Corn Rootworm-Protected B.t. corn, and Corn Borer/ Corn Rootworm-Protected Stacked B.t. corn. Project Number: CAP/2007. Unpublished study prepared by Agricultural Bi otechnology Stewardship Technical Committee. 17 p.

EPA MRID No.47356701 Lefko, S.; Binning, R. (2008) Characterization of Instar-Specific Response and Larval Recovery of Western Corn Rootworm Exposed to 59122 Maize. Project Number: PHI/2005/053.Unpublished study prepared by Pioneer Hi-Bred In ternational, Inc. 34 p.

EPA MRID No.47356702 Lefko, S.; Binning, R. ( 2008) Effect of Off-Type Seeds on the

Precision of Sublethal Corn Rootworm Seedli ng Assay Results. Pr oject Number: PHI/2006/042. Unpublished study prepared by Pioneer Hi -Bred International, Inc. 13 p.

EPA MRID No.47356703 Lefko, S.; Diehn, S. (2008) An Observational Study Characterizing the Relative Quantity and Distribution of Cr y34Ab1 and Cry35Ab1 Insecticidal Proteins in Roots of Maize Containing Event DAS-59122-7. Project Number: PHI/2006/119. Unpublished study prepared by Pioneer Hi-Bred International, Inc. 22 p.

EPA MRID No.47356704 Lefko, S.; Binning, R. ( 2008) Quantifying the Concentration of Cry34Ab1 and Cry35Ab1 in 59122 Maize Grown in the Sublethal Corn Rootworm Seedling Assay System. Project Numb er: PHI/2006/171. Unpublished st udy prepared by Pioneer HiBred International, Inc. 11 p.

EPA MRID No.47356705 Nowatzki, T. ; Thompson, S.; Peters, M. (2008) Field Measures of Adult Corn Rootworm (Coleoptera: Chrysomelid ae) Production When Refuge is Deployed as a

Seed Blend with DAS-59122-7 Maize. Pr oject Number: PHI/2007/ 075. Unpublished study prepared by Pioneer Hi-Bred International, Inc. 57 p.Optimum AcreMax B.t. Corn S eed Blends Page 21 of 23 Biopesticides Registration Action Document

EPA MRID No.47356706 Nowatzki, T.; Meinke, L. (2008) Impact of Western and Northern Corn Rootworm Larval Exposure to DAS-59122-7 in a Block Planting and a Seed Blend on Life History Traits of Adults. Project Numb er: PHI/2007/076. Unpublished study prepared by

Pioneer Hi-Bred International, Inc. and Un iversity of Nebraska-Lincoln. 31 p.

EPA MRID No.47356707 Lefko, S.; Binning, R. (2008) I nvestigating the Effect of Insecticidal Proteins Cry34/35Ab1 on Western Corn Rootworm Host Searchi ng Behavior. Project Number: PHI/2007/126. Unpublished study prepared by Pion eer Hi-Bred Internat ional, Inc. 17 p.

EPA MRID No.47356710 Davis, P.; MacIntosh, S. (2008) Benefits Document for Optimum AcreMax 1 Insect Protection. Project Numb er: PHI/2007/145. Unpublished study prepared by Pioneer Hi-Bred International, Inc. 21 p.

EPA MRID No.47663301 Bailey, L. (2009) 2008 In sect Resistance Management Compliance Assurance Program Report for Corn Borer-Protect ed B.t. Corn, Corn Rootworm-Protected B.t. Corn, and Corn Borer/Corn Rootworm-Protect ed Stacked B.t. Corn. Project Number: CAP/2008. Unpublished study prepared by Agri cultural Biotechnology Stewardship Techn. Committee. 15 p.

EPA MRID No.47683801 Binning, R.; Langer, D. ( 2009) Additional Responses for "Pioneer's Benefit Documentation in Support of a Sec(3) Product Registration for Optimum AcreMax 1 Insect Protection, also Known as Stack Hercul ex XTRA (Cry34/35Ab1 + Cry1F) with Herculex I (Cry1F, Refuge Seed for CRW) [MRID 473567- 10 and Supplemental Data]": Final Report. Project Number: PHI/2009/026. Unpublished study pr epared by Pioneer Hi-Bred International, Inc. 11 p.

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