### . UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D
.C. 20460



### Elizabeth Owens, Ph.D. Chair Agricultural Biotechnology Stewardship Technical Committee c/o Pioneer · 7100 NW 62"d Avenue Johnston, TA 50131-1000 Dear Dr. Owens: OFFI CE OF CHEMI CAL SAFETY AND POL LUTION PREV ENTI ON


### September 3, 2014

We are writing to initiate discussions with Bt corn registrants (via the Agricultural Biotechnology Stewardship Technical Committee) on improvements to corn rootworm resistance management. As you are aware, ABSTC and EPA share a common interest in preserving the durability ofBt corn traits to control corn rootworm. Along these lines, the Agency convened a Science Advisory Panel (SAP) meeting in December 2013 to address scientific uncertainties associated with corn rootworm resistance monitoring. These discussions will follow from the recommendations made by the panel in its report dated March 5, 2014. To aid in starting the discussions, the Agency is enclosing a set ofproposals developed by the Biopesticides and Pollution Prevention Division to enhance current resistance management and monitoring programs for corn rootworm. These proposals are consistent with the SAP' s guidance and cover five aspects ofIRM, including the following:
• Integrated Pest Management (IPM) as a component ofcorn rootworm resistance management • Responses to unexpected damage in Bt corn fields • Elimination ofthe requirement for annual random sampling ofcorn rootworm from the Corn Belt • Use ofon-plant assays for resistance determinations • Enhancements to current remedial action plans The Agency's goal is to have improvements in place for the 2015 growing season. To meet this goal, we are asking that you submit a response to the attached proposal by September 21,2014. EPA would like to finalize the agreement/enhancements to the affected Bt corn products by October 31, 2014
.If you would like to schedule a meeting to discuss this further after you've responded to our proposal, or if you have any questions or concerns, please contact Alan Reyno l ds ( reynolds.alan @ epa.gov ; 703-605-0515). Enclosure

Sincerely, · mberly Nesci, Chief Microbial Pesticides Branch Biopesticide and Pollution Prevention Division - 2 -EPA Framework for PIP Regis trants: Proposal to Address Key SAP Recommendations for Corn Rootworm (CRW) IRM Draft Date: 8/27/14 Ove rall Goal: BPPD has identified five areas of improvement for corn rootworm resistance management
. These measures are needed to increase t he d u rability of CRW Bt PIPs (so as to reduce the potentia l need for remediation), and to i mprove on current abi l it ies to detect and respond to cases of resistance. BPPD is ta rget i ng these improvements to be i n place for the 2015 g rowi ng season. 1) Utilize an IPM approach to CRW resistance management
• Rationa le: o Given the documented cases offie ld resistance to some Bt t raits, refuge alone has not been sufficient to manage CRW resistance to B t corn; o The SAP conclu ded (and EPA ag rees) that sound I PM p ractices may red uce the potentia l for res istance (and hence remediation)
. • Goals : o I PM stewardsh i p program. Reg istrants must supplement IRM (ref uges) with I PM techn iques. Th is can be i mplemented by registrants as a s t ewardship program as part of the terms of registration that must include t he followi ng specific IPM approaches : • Crop rotation with no mo re tha n two consecut ive yea rs of Bt corn (preferab ly rotat i ng to soybean)
. Rotation can be accompl ished on a farm -w ide basis or fie ld- by-fie ld with in a fa rm; • Use of multip le Bt modes of act ion for CRW control, preferably in pyramided va riet ies (4 Bt PI Ps are cu rre ntly registered: Cry3Bb1, Cry34/35 , mCry3A, and eCry3.1Ab) ; AND • Use of non - Bt (conventional) corn wi t h i nsecticide use for CRW management; o Adoptio n ta rgets
. The stewardship prog ram must establ ish adopt ion targets for the IPM elements ( i.e
.,% of g rowers and total corn acres planted w ith each company's seed using each IPM approach), as defi ned be low . A two t ier system is envisioned , with separate targets fo r h igh risk areas ( i. e., t he "Red Zone") and lower risk areas 

### (i.e., the "fri nge" of the Corn Belt). IPM Adoption (%oftotal acres) High Risk Areas Lower R isk Areas Overa iii PM participation 70 50 Tact ics to be used among I PM participants:

- Crop rotation 50 33

- Mu lt i ple modes of 25 33

action/py ramids

- Non- Bt corn w/SAI 25 33 Use of si ngle toxin PI Ps No more than 10% No more than 20%

1o Annual repor t ing. The program would require annual report ing to EPA of success in meeting the IPM targets ( i.e ., how many growers chose to implement crop rotation, py rami ds, etc.). Each company would report data ind i v i dually based fo r the i r custome r s (surveys could be conducted similar to those done fo r refuge comp li ance). BPPD w ill analyze the reports and tabulate data ac r oss the in d ustry as a whole; o Single trait PIPs. The stewardship program and report in g must include information on progress towards r eplacement of single-trait CRW commercial PIP products; • No n - starter:o Soi l -applied i nsecticides (SAl). SAis must be prohib it ed from use in combination w i th Bt corn for cont rolling corn rootworm. This can be done via bag tag language, grower guides, and terms of

reg i strat i on. • Challenges to be addressed : o Need for coo r d inatio n between companies, particularly among g r owers who may purchase seed from more than one company (a program analogous to the existing comp l iance assurance program could address this challenge); o Need for means to address neighboring farms; o Implementation of SAl prohib ition. 2) Implement a proactive strategy to detect unexpected damage (UXD) in Bt corn fields • Rationale: o UXD is the f i rst rea l ind i cator of potentia l resis tance; o Cases of resis t ance to date have been documented by collecting CRW from damaged fields ; o Effect iv e and t imely res ponses to UXD may aid remed i ation (if res is tant CRW are responsible). • Goals: o Damage thresholds. Revise te r ms and conditions to require the use of damage t h resholds to trigger CRW sampling for resistance determ i nat i ons: 1.0 Node Injury Score (NIS) for s i ngle traits and 0.5 NIS for pyramids; o Adult collection. Revise term and conditions to requ i re collection of adults from the damaged site (or same f ie l d if collections are delayed that season) and that those adults be tested for resistance with on-plant assays (see #4 below); o Immed i ate impleme n tation of BMPs. Revise terms and conditions to r equire, in c ases of UXD, that BMPs be implemented immediately (i.e., before resistan ce conf i rmation) to mitigate the spread of a potentially resistant population. BMPs are essentially the same IPM practices that

were detailed in #1 above but may include beetle bomb in g to reduce egg lay in g the next year. o Target adoption l evel for BMPs. At leas t 75%, s i milar to the IPM ta r gets fo r high risk areas in #1 above. • Challenges to be addressed: o Many elements are currently in place (e.g., damage triggers and BMPs for UXD) but there is a need for standardization across the industry; 2

### o Need for improvement of detection capabilities in high risk areas- better scouting, possibly involving crop consultants, un iversity extension personnel, company representat ives (registrants currently rely sole ly on growers to report UXD); o Mechanism for reporting UXD cases and their resolut ion to EPA. One possible tool could be to use EPA's Central Data Exchange (COX). COX is a secure means to report i nformat ion to EPA (used in the Air program) and could be used to tabulate UXD damage reports by toxin and geog raphic location
. This information could be used in inform remedia l action strategies (see #5 below). 

### 3) Remove requirement for annual monitoring of CRW populations randomly sampled from the Corn Belt

• Ratio nale: o EPA has concluded that data aren't mean i ngful unless popu lat ions are tracked over time; o Panel recommended tracking individual populations or discrete geograp hi c locations based on high risk factors, but such tracking will be inefficient and unl ike ly t o detect resist ance befo re fie ld failure; o BPPD believes it will be mo re effective to focus instead on proactive detection and response to UXD (#2 ab ove). • Goals: o I ndustry to mod ify terms of registration to remove annual sampling requirements (coup led with improvements to UXD scouting deta i led in #2 above). 

### 4) Improve resistance confirmation process by replacing artificial diet bioassays with "on-plant" assays • Rationa le: o EPA has concluded that diet bioassays have not been he l pful for regulatory purposes- data are too variable to reliably draw conclusions about resistance; o EPA believes that on-p lant assays represent a more realistic exposure scenario and can serve as a diagnostic tool; o EPA unde rstands that two on -plant assays have been developed (with methodology in the public literature) to confirm resista nce: single on - plant assay (Gassmann) and Sublethal Seedl ing assay (P ioneer). • Goals: o I ndustry to mod ify terms of registration to mandate the use of an on-plan t assay and resistance confirmation cri t eria; o Resistance is confirmed by comparing a popu lation's response on Bt vs . non-Bt corn and/or with a susceptible control population (2 statistically significant comparisons are needed to confirm resistance); • Challenges to be addressed: o How to ensure consistent resistance determination standards with two separate assays (si ngle on-plant vs. SSA); o Adaptation of the on-plant assays for the d ifferent registered Bt t oxin s, particula rly the SSA which was developed for Cry34/35 corn; 

### 3o Transition for compan i es current l y using the diet bioassay. S) Enhance current remedial action (RA) plans (in the event of documented res i stance) • Rationale: o The panel recommended that specific, implementable RA plans be developed pr i or to resistance confirmation ( currently registrants are required to work w i th EPA to develop a plan ex post facto); o The goals of RA are to 1) contain (a n d exti r pate if possible) res i stant populations, and 2) preserve the du r ab i lity of Bt CRW traits in areas where they are still effective. • Goals: o Remedial action plans. Registrants must develop and submit RA p l ans to be in place prior to resistance development; o Standards. Remedial act i on plans must identify industry-wide standards as follows: • Timing: RA plan must ensure act i on ( I PM - based BMPs from #2 above) occurs i mmediately in response to UXD (i . e., within the growing season) and should continue in subsequent seasons unless res i stance is disconfirmed; • BMPs: RA plan must require the follow i ng specific steps t aken for UXD and/or resistance: • Adult CRW t r eatment ( " beetle bomb i ng") in UXD damage fields (same season); • Crop rotation (preferred), use of alternate Bt modes of action, use of pyram i ded variet i es, or non-Bt corn (with insect i cides) i n subseq u ent seasons; • Geography: RA plan must describe how to define the scope of RA . The RA area as defined in the plan must include not j u st the affected field but surrounding f i elds and

farms within the dispersal range of CRW. (This could also be informed by UXD r eports r eceived by COX - see #2 above). o Data needs. Add i t i onal r esearch is needed to imp r ove RA including CRW dispe r sal in simulation models to ass e ss the potential spread of r esistant populations and would en t er t ain revised plans

based on the r esu l ts of any such research; o Notification s y stem. RA plan must require cases of documented resistance to be publ i cly reported o n web site (either by ABSTC, the individual company, o r EPA) . This would help growers make informed decisions about CRW management options. • Challenges to be addr e ssed: o Def i ning the remediat i on zone, which could involve mu l t i ple farms and customers from different registrants; o Need for coord i nation between companies; o Need for addi ti onal research to scientifica ll y deli n eate remedia ti on areas (the SAP also p r oposed a number of t e ch n iques to do this); o Encourag i ng growers to im plement effective measures (e.g . , crop rotat i on) that may differ from the i r farming p ractices . 4