AGENDA

US ENVIRONMENTAL PROTECTION AGENCY (EPA) 

FIFRA SCIENTIFIC ADVISORY PANEL (SAP) 

OPEN MEETING 

DECEMBER 4-6, 2013

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/ 

Docket Number: EPA-HQ-OPP-2013-0490 

U.S. Environmental Protection Agency

Conference Center Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Scientific Uncertainties Associated with Corn Rootworm Resistance Monitoring for Bt 

Corn Plant Incorporated Protectants (PIPs)

Please note that all times are approximate (see note at end of Agenda). 

Day 1 

Wednesday, December 4, 2013

9:00 A.M. Opening of Meeting and Administrative Procedures 

Fred Jenkins, Ph.D., Designated Federal Official, Office of Science Coordination 

and Policy, EPA 

9:05 A.M. Introduction and Identification of Panel Members 

Daniel Schlenk, Ph.D., FIFRA Scientific Advisory Panel Chair 

9:10 A.M. Welcome and Opening Remarks 

Steven Bradbury, Ph.D., Director, Office of Pesticide Programs (OPP), EPA

Robert McNally, Director, Biopesticides and Pollution Prevention Division

(BPPD), OPP

9:25 A.M. Scientific Uncertainties Associated With Resistance Monitoring for Corn 

Rootworm

Alan Reynolds, OPP, Biopesticides and Pollution Prevention Division

10:30 A.M. Break

10:45 A.M. Scientific Uncertainties Associated With Resistance Monitoring for Corn 

Rootworm (Cont’d)

Alan Reynolds, OPP, Biopesticides and Pollution Prevention Division

11:45 A.M. Lunch

1:00 P.M. Public Comments

2:30 P.M. Break
2:45 P.M. Public Comments (Cont’d)

3:45 P.M. Panel Discussion of Charge Questions

Charge Question 1.

a. The panel is asked to comment on sampling approaches for conducting annual 

CRW resistance monitoring that support early resistance detection. Please discuss 

the strengths and limitations of BPPD’s proposal for a focused (risk based) 

sampling approach for the Corn Belt, supplemented with samples from lower risk 

“fringe” areas for comparison.

b. How many CRW populations should be collected from within a sampling region 

to adequately assess susceptibility?

4:30 P.M. Panel Discussion of Charge Questions

Charge Question 2.

a. The panel is asked to comment on methods for investigating CRW populations 

causing unexpected damage to Bt corn. Specifically, please comment on:

 

ii. The use of field damage ratings (NIS) as a screen for potentially resistant 

populations. What sampling triggers should be used for single toxin and 

pyramided Bt products? Should alternate techniques be considered?

iii. The use of transect sampling in damaged areas or random sampling 

throughout the affected field to assess root damage ratings. 

5:00 P.M. Adjourn
Day 2 

Thursday, December 5, 2013 

9:00 A.M. Opening of Meeting and Administrative Procedures 

Fred Jenkins, Ph.D., Designated Federal Official, Office of Science Coordination 

and Policy, EPA 

9:05 A.M. Introduction and Identification of Panel Members

Daniel Schlenk, Ph.D., FIFRA Scientific Advisory Panel Chair 

9:10 A.M. Follow-up from the previous day discussions 

9:40 A.M. Panel Discussion of Charge Questions 

Charge Question 2. (Cont’d)

iv. Appropriate sampling locations (i.e., in the vicinity of the damage and/or 

surrounding areas) for collections of adults if field damage triggers are exceeded.

 

v. The deployment of sentinel plots in the vicinity of damaged fields in subsequent 

seasons to 1) assess the resistance allele frequency in the area, and/or 2) collect 

insects if no adults were present at time of the field investigation.

10:40 A.M. Break

11:00 A.M. Panel Discussion of Charge Questions

Charge Question 3.

a. Please comment on the strengths and limitations of diet bioassay methodologies 

for early resistance detection with CRW, considering that the currently-registered 

toxins are less than high dose. What improvements could be made to these 

bioassays to make them more effective and proactive resistance detection tools? 

b. The panel is asked to discuss the relative merits and limitations of the two onplant assays (Gassmann et al. 2011 and Nowatzki et al. 2008). Please discuss the 

extent to which these assays have different sensitivities to make early corn 

rootworm resistance determinations? Should other on-plant assay approaches be 

considered?

12:00 P.M. Lunch

1:00 P.M Panel Discussion of Charge Questions
Charge Question 4.

a. The Panel is asked to discuss the merits and shortcomings of the proposed 

approaches to defining resistance using on-plant assays. What sets of comparisons 

in the assays are most likely to add value to a weight-of-evidence approach to 

determining resistance?

b. What resistance allele frequency should constitute field resistance for toxins with 

less than high dose expression? Please discuss the criteria that should be used for 

these types of toxins (as opposed to high dose toxins) given that a portion of 

heterozygous insects will survive Bt exposure and drive the evolution of 

resistance.

c. What statistical tests, criteria, and significance levels would be best suited for 

early resistance detection with the proposed assays? Please discuss how to best 

avoid false negatives and/or false positives.

2:30 P.M. Break 

2:45 P.M. Panel Discussion of Charge Questions

Charge Question 4 (Cont’d)

d. Please comment on the extent to which incomplete resistance can be identified 

with on-plant test systems. How should resistance definitions be adjusted to 

address these scenarios?

e. Please discuss the viability of resistance ratios as an option for determining 

resistant populations, considering the generally low susceptibility of CRW to Bt 

toxins and the lack of susceptible wildtype populations (i.e., due to widespread 

adoption of Bt corn). What ratio could be considered as an indicator of resistance 

for corn rootworm using on-plant assays?

Charge Question 5.

a. Please comment on the strengths and limitations of BPPD’s proposal to use 

resistance allele gradients to define the geographic extent of a resistant 

population. 

b. What other tools or strategies could be employed to define the remediation zone?

5:00 PM Adjourn
Day 3 

Friday, December 6, 2013

9:00 A.M. Opening of Meeting and Administrative Procedures 

Fred Jenkins, Ph.D., Designated Federal Official, Office of Science Coordination 

and Policy, EPA 

9:05 A.M. Introduction and Identification of Panel Members 

Daniel Schlenk, Ph.D., FIFRA Scientific Advisory Panel Chair 

9:10 A.M. Follow-up from the previous day discussions

9:30 A.M. Panel Discussion of Charge Questions (Cont’d)

Charge Question 6.

a. What remediation approaches could be taken for localized vs. area-wide resistance 

scenarios?

b. Which mitigation measures would be more effective in containing and/or extirpating 

resistant CRW populations? 

c. Please comment on the value of theoretical models in designing remedial action 

strategies for various resistance scenarios. 

d. The current deterministic and stochastic simulation models used for IRM purposes 

contain many of the following attributes: ecology, population biology, behavior, and 

genetics of pest, grower behavior (refuge compliance, insecticide spraying, etc), 

explicit spatial and probability analyses. What other modeling attributes would help 

improve the analysis of remediation strategies? 

12:00 P.M. Adjourn

Please be advised that agenda times are approximate; when the discussion for one topic is 

completed, discussions for the next topic will begin. For further information, please contact 

the Designated Federal Official for this meeting, Dr. Fred Jenkins, via telephone: (202) 564-

3327; fax: (202) 564-8382; or email: jenkins.fred@epa.gov