April	3,	2013 Comments	for

FIFRA	Scientific	Advisory	Panel Scientific	Uncertainties	Associated	with	Corn	Rootworm	Resistance	Monitoring	for	Bt	Corn Plant	Incorporated	Protectants	(PIPs) Docket:	EPA

- HQ

- OPP

- 2013

- 0490

by	Center	for	Food	Safety

Emailed to: Fred	Jenkins,	DFO,	Office	of	Science	Coordination	and	Policy	(7201M) Environmental	Protection	Agency 1200	Pennsylvania	Ave.,	NW Washington,	DC	20460

- 0001 Jenkins.fred@epa.gov



## Summary of	Comments

CFS	gener ally	agrees	with	EPA’s	proposed	changes	to	corn	rootw orm	(CRW)	resistance monitoring.		However, such	changes	will	not	significantly	deter	further	emergence	of Bt

resistant	CRW	unless they	are accompanied	by	a	substantial	strengthening	of	the	resistance pre vention components	of	insect resistance	management	(IRM).

Monitoring	has	revealed	declines	in	susceptibility	to	all	of	the	commercial rootworm	toxins since	2005;	and	escalating	emergence	of	Cry3Bb1

- resistant	CRW	since	no	later	than	2009. First	identified by	independent	scientists in	Iowa	and	Illinois,	resistant	CRW	are	likely present	in	multiple	regions	of 11	states	based	on	reports of	unexpected	damage to	Bt	corn reviewed	by	EPA	(see	section	II.A).		This	rapid	emergence	of	resistance	is	attributable	to

s everal	factors:

1) Increased	continuous	corn	cultivation	that	has	been	facilitated	by	Bt	corn and encouraged	by	its	developers (see	II.D);

N ATIONAL O FFICE : 660	Pennsylvania	Ave.,	S.E.,	Suite	302,	Washington,	D.C.	20003 phone: 202

- 547

- 9359 fax: 202

- 547

- 9429 C ALIFORNIA O FFICE : 303	Sacramento	Street,	2nd	Floor,	San	Francisco,	CA	94111 phone: 415

- 826

- 2770 fax: 415

- 826

- 0507 P ACIFIC N ORTHWEST O FFICE : 917	SW	Oak	Street,	Suite	300,	Portland,	OR	97205 phone: 971

- 271

- 7372 fax: 971

- 271

- 7374 email: office @ centerforfoodsafety.org | www.centerforfoodsafety.org | www.truefoodnow.org2 2) Sharply	reduced	availability	and	planting	of	conventional	(or	non

- Bt)	corn	seed,	a key	IRM	measure	(see	II.C);

3) The rise	of	resistance

- promoting,	volunteer Bt corn	as a	weed,	made	more	difficult to	control	when	stacked	with	herbicide

- resistance	traits	( see II.E);	and

4) Most	importantly, EPA’s	irresponsible	reductions	in	refuge	size	requirements	to levels	much lower than	are	needed	to	dilute	resistance	genes	and	deter	res istance ( see II.B).

EPA’s	failure	to	stem	resistance	in	CRW	can	be	explained	in	several	ways (see generally IV)

. First,	there	has	been	misplaced application	of	IRM	for	lepidopteran	Bt	corn	to	the	very different	resistance	challenges	prese nted	by	rootworm

- active	Bt	corn.		Second,	a n	overly stringent	definition	of	resistance	has	resulted	in	numerous	false	negative	findings	and	thus delayed	effective	remedial	action	for	years (I:	Question s	4	and	6) .		Finally,	EPA	has	relied excessively	on industry	views	and assessments	that	are	skewed	by	financial	self

- interest ; and	rejected	the unbiased	analysis and	recommendations of	independent	experts,	as	seen most	clearly	in	refugia	requirements	that	are	much	too	low	to	dilute	resistance	genes	and forestall	resistance (I I.B)

.

CFS	recommends	that	EPA:

1) Make	publically	available	the	monitoring	data	reported	to	EPA	re:	unexpected damage	to	Bt	corn,	and/or	provide	complete	descriptions	of	it	in	relevant documents	released	to	the	public	(II.A)

2) Establish	a	simple, single

- criterion	definition	of	resistance	along	the	lines	discussed in	section	I,	Question	4

3) Increase	refuge	requirements	for	all	rootworm

- active	Bt	corn	events	to	50%	for single

- toxin	Bt	corn	and	20%	for	pyramids	(II.B)

4) Establish	mandatory	IRM	involving rotation away from	rootworm	Bt	corn	(IV)

5) Increase	the	role	of	independent	scientists	and	reduce	that	of	seed	firms	in	every aspect	of	IRM	in	light	of industry’s	failure	to	successfully	detect	and	notify	EPA	of the	emergence	of	resistant	CRW	(IV)

## Comments

Center	for	Food	Safety (CFS) appreciates	th e	opportunity	to	comment	on	the	growing resistance	of	corn	rootworm	to	Bt	toxins	and	EPA’s	propos als	to	im prove	monitoring	for resistance	and	remedial	action.

CFS	generally	agrees	with	EPA’s	proposed	changes	to corn	rootworm	( CRW ) resistance monitoring .		However,	while	these changes would perhaps	deliver marginal	improvements, they would	not	significantly	det er	further rapid emergence	of	Bt toxin

- resistant	CRW.		To achieve	this would	require	more	thoroughgoing	reform	of	the	insect	resistance management	p lans

. In	these	comments,	we	first	address	the	specific	charge	questions, followed	by a	discussion	of issues not	addressed	by	EPA	and of measures	that do	have	the potential	to	significantly	deter	further	emergence	of CRW resistance.



## I. Comments	on Charge	Questions

Question	1:	Annual	Corn	Rootworm	Sampling	to	Assess	Bt	S usceptib i lity CFS	agrees	with EPA that IRM	monitoring	should	involve	more intensive	and	focuse d sampling .		This	approach	would	seem	to	be	more	consistent	with	the	primarily	short

distance	dispersal	patterns	of	CRW	adults,	as	well	as	the observed	emergence	of	resistant CRW	populations primarily in	localized	hot	spots. However, corn	rootworm	has	shown	the capacity	for	fairly	rapid	dispersal	over	long	distances.		First,	CRW expanded	eastward across	the Corn	Belt	in	the	1960s	and	1970s at	rates	ranging	from	20	to	200	km/year, depending	in	part	on	t he	direction	of	prevailing	winds and storm	fronts .		Second

, rotation

resistant CRW	has	expanded	its	range	from	its	origins	in	eastern	Illinois	in	1987	to	infest parts	of	seven	states	in	2007,	just	20	years	later.		Finally,	CRW	first	discovered	in	Europe

ne ar	Belgrade	in	1992	was	found	in	20	European	countries	just	15	years	later	in	2007 1 (Gray	et	al	2009 ,	see	map s below ).		Thus, EPA	must	not	neglect	the	potential for	longer

distance	dispersal	of	resistant	CRW	from	numerous	hot	spots,	which is	likely	already leading	to rapid	emergence	of	ar ea

- wide	resistance. Random	sampling	is	better	suited	to detect emergence	of	area

- wide	resistance,	and	should	remain	part	of	annual	monitoring together	with	more	intensive	and	focused	sampling.

Current	monitoring	involves random	sampling	of	just	12

- 15	populations	each	year	in	three states.		Clearly,	many	more	populations	will	have	to	be	sampled	with	incorporation	of	the intensive,	focused	sampling	approach.		The	number	of	CRW	populations	that	are	sampled should	increase	in proportion	to	the	number	of	unexpected	Bt	damage	reports,	and intensive	sampling	should	be	focused	in	those	areas.

1 CRW’s	expansion	in	Europe	is	due	to	some	combination	of	multiple	introductions	from	the	U.S.	(at	least	3) and	subsequent	range	expansion	from	these	foci.4 Source :	Gray	et	al	(2009)

Source: Gray	et	al	(2009)5 Source: Gray	et	al	(2009).



### Question	2:	Corn	Rootworm	S ampling	in Response	to	Damaged	Bt	F ields EPA	recommends	use	of	field	damage	ratings	based	on	root	node	injury	for	investigations of	CRW	populations	causing	damage	to	Bt	corn.		The	triggers suggested by	EPA	are:	1.0	for single

- toxin	Bt	products	and	0.5	for	pyramided	B t	products.		CFS	recommends	that	EPA utilize	the	0.5	rating	for	both	categories.		This	would	be	consistent	with	the	expert recommendation	of	the 2002	Scientific	Advisory	Panel (SAP) that	advised	EPA	on	insect resistance	management	for Cry3Bb1

- expressing MO N863 corn .		This	SAP	advised that CRW root	damage	“approaching	a	0.5	(node

- injury	scale)”	on	MON863	roots,	coupled	with	a history	of	MON863	cultivation,	was	sufficient	to	regard	a	CRW	pop ulation	as	“suspected resistant ” (SAP	2002

, pdf p.	65 2 ).

It	is	uncl ear	why	greater	damage	should	be	needed	to	deem	a	CRW	population	resistant	or suspected	resistant	in	the	case	of	single

- toxin plants .		For	example,	at	present	Cry34/35Ab1

2 Pdf	page	number s ( e.g. page	65	of	71) are	cited	for	this SAP	report because	it does	not	have printed page numbers.6 appears	to	be	the	only	commercial	rootworm	PIP	t hat	remains	largely	uncompromised	by resistant	CRW, in	light	of	the strong	evidence	for cross

- resistance	between	Cry3Bb1	and mCry3A (BPPD	2013c,	p	24) .		It is	thus	extremely	important	that	its	efficacy	be	preserved ; and	its	effectiveness must	be	safeguarded	as	fully	when	deployed	in	a	single

- toxin plant as when	deployed	in	a	pyramid	( e.g. SmartStax	corn)

. This	is	true	not	only	for	Cry34/35Ab1 ; it	applies	more	generally.		EPA	should	establish the	same	damage	trigger

– 0.5	node	injury

– for single

- toxin	and	pyramided	seeds in	resistance assessments.

In	the	charge	question,	EPA notes	that	some	unidentified	party	or	parties	has	raised	a concern	that	sampling	for	adult	CRW	directly	in	damaged	Bt	fields,	specifically	in	the vicinity	of	the	damage,	“may	be	biased	relative	to	surrounding	areas and	not	representative of	the	overall	CRW	population.” Some	such	concern	may	well	have	been well	have	been what	motivated	Monsanto	to	propose	a	sampling	plan	in	response	to	damage	reports	in which	CRW	were	collected	as	far	as	one	to two miles	from	failed fields (BPPD	2011,	p.	2).

This	concern,	however,	is	entirely	misplaced,	based	on	a	misunderstanding	of	the	nature	of CRW	resistance	and	the	purpose	of	this	part	of	the	monitoring	program.

First,	because	CRW	resistance	to	Bt	toxins	is	li kely	to	arise	( at least	initially )	in	numerous confined	areas ,	collecting	CRW	samples	far	away	from	damaged	Bt	corn	would	introduce	a clear	bias	tending	towards	false	negative	results.		As EPA	noted with	respect	to the Monsanto	plan	mentioned	above:	“this	proposal	is	insuff icient	if	the	goal	is	to	determine whether	Bt	failure	is	due	to	resistance	of	the	CRW	population”	(BPPD	2011,	p.	2).		CFS
agrees.
Second,	the	primary	purpose	of sampling in	response	to damage reports	is damage	control

– rapid assessment of probable resist ance,	followed	by	strong	and	effective	remedial	action to	contain	and	extirpate	it ,	as	needed .		The	purpose	is not

– as it	has	been with	annual sampling

– to	provide	early	indications	of	evolving	resistance on	an	area

- wide	basis,	in which	case	broader	samp ling	would	make	more	sense.		However,	as	discussed	above,	CFS agrees	with	EPA	that	annual monitoring should incorporate	more intensive	and	focused sampling

. For	both	of	these	reasons,	sampling	of	CRW	adults in	response	to	unexpected	damage should	be	focus ed	directly	in	the	damaged	area	of	Bt	fields	and	the	immediate	vicinity	as much	as	possible.



### Question	3:	Diagnostic	A ssays CFS	supports	EPA’s	recommendation	that	diagnostic	on

- plant	assays	be	the	primary resistance	detection	tool	for	corn	rootworm.		CFS recommends	use	of	the	Gassmann	assay, which	has	proven	itself	capable	of	detecting	resistance	where	diet	bioassays	have ( perhaps ) failed. 3 As	EPA	notes	in	its	white	paper,	neither	the	instar	development	nor	body

3 We	say	“perhaps	failed”	because	i n	EPA’s	white	paper (page	16), it	is	stated	that	field	populations of	CRW that meet	a	key	resistance	criterion	(LC50s	exceeding	the	upper	limit	of	the	95%	confidence	interval	of	the control	populatio n)	have	been	identified	with	use	of	diet	bioassays ,	apparently	for	all	three	CRW	Bt	toxins,7 size	criteri a employed	in the	sublethal seedling	assays	(e.g. Nowatzki	et	al	2008 ) has	been validated	as a	reliable	marker	of	resistance.

“ BPPD	notes	there	is	no	evidence	demonstrating	that	resistant	corn rootworm	need	to	have	greater	body	mass	or	head	capsule	widths	for development	than	the ir	susceptible	counterparts. Hence, this	significance criterion	is	likely	too	stringent	and	would	potentially	result	in	false negatives

. ”	( White	paper, p.	17)

Whenever	diagnostic	assays involve	comparisons	to	susceptible	CRW	populations (whether	contempo rary	or	historical	data),	c are	should	be	taken to	ensure	that	the susceptible	standard	of	comparison	represents	truly	susceptible	CRW	prior	to	any	selection
pressure from	exposure	to	Bt	rootworm	toxins .		EPA notes	that	“[i]n	some	cases,	lower susceptibilit y	has	been	observed	in	field	populations	relative	to	the	laboratory	colonies” (White	Paper,	p.	15);	and	similarly: “ CRW	populations	in	the	field	have	experienced selection	to	Bt	corn	over	the	past	decade	and	likely	have	obtained	some	degree	of	tolerance
to the	toxins (Cry3Bb1,	mCry3A,	and	Cry34/35)”	(White	paper,	29).		Use	of	“less susceptible”	or	partially	tolerant	CRW	for	control	purposes	in	resistance	assessments	is	to be	avoided	whenever	possible ; or if	not	avoidable, accounted	for in	resistance	assessm ents by ,	for	example, reducing the	resistance	ratio or	other	comparative	metric required	for diagnosis	of	resistance.


### Question	4:	Defining	Resistance EPA’s ostensible goal	is	to	make	resistance	monitoring	proactive	rather	than	reactive.		To that	end, the Agency recognizes	that	resistance	must	be	defined	such	that	an	“actionable threshold”	is	met	before	resistance	is	widespread ( W hite	paper ,	p.	22). If resistance	is	not defined	in	this	way;	if timely regulatory	action	is	not	possible	due	to	an	excessively stringent	definition	of	resistance ;	then IRM	completely	fail s to	serve	its	intended	purpose; the	Bt	toxin’s	value	is	lost	or	eroded;	and	chemical	insecticide	use	rises,	with	associated toxicity	to	human	health	and	the	environment. In	EPA’s	terms,	“populat ion	suppression (e.g.	chemical	insecticide	use)	may	be	the	only	alternative	for	managing	resistance”	( White paper,	p.	22)

.

Results	of	a prospective survey	conducted	by	University	of	Illinois	entomologist Michael Gray	s how that	in	2013, nearly 50%	of	Ill inois	corn	growers expected	to use	both	Bt	corn with	rootworm

- active	toxin ( s ) AND	chemical	insecticides (Jongeneel	2013) .		University	of Minnesota	entomologist	Ken	Ostlie	expected	similarly	high	use	of	insecticides,	both	on continuous	corn	and	rotated	corn :
"At	winter	meetings	with	ag	professionals,	they	indicated	more	than	50 percent	of	corn

- on

- corn	would	end	up	with	an	insecticide	overlay	of	traits,"

“although	none	of	the	populations	have	been	de emed	resistant	by	registrants... [p]resumably	...	due	to	the difficulty	of	interpreting	and obtaining	accurate	LC50	value s. ” Thus,	t he	problem	may	lie	less	with	the	type	of assay	than	with how	it	is	interpreted,	and	who	is	doing	the	interpreting.		Below,	we	discuss	how	corporate financial	interests	may	be	skewing	the	science	and	regulation	of	IRM.8 says	Ostlie.	"About	25	to	30	percent	of	rotated	corn	with	no	threat	of resistance	was	expected	to	receive an	overlay. I	suspect	final	percentages	of both	were	higher." (Ruen	2013)

This evidence shows that	resistance 4 is	already prevalent	enough	to	be driving	up	the	use of	insecticides	substantially.

Despite EPA’s goal to	make	IRM	proactive ,	however,	its c urrent	and	proposed	definitions	of resistance ensure its continuing	failure	for	corn	rootworm.		As	EPA	itself	concedes :
“All	of	the	proposed	procedures	are	likely	to	detect	resistance	only	if	it	is complete	(i.e.,	CRW	develop	and	survive	on	Bt corn	at	the	same	levels	as isoline	corn). Comparisons	of	field	populations	on	Bt	and	non

- Bt	corn require	statistical	equivalence	to	make	a	positive	resistance	determination. This	statistical	approach	would	exclude	cases	of	incomplete	resistance,	in whic h	a	field	population	is	more	fit	than	a	control	colony	on	Bt	plants	but	not as	fit	as	a	population	with	complete	resistance.”	( White	Paper,	p. 29)

The	definition	of	resistance	must	be	revised	to encompass partial	resistance. This	is particularly	importan t	given	the	ongoing	emergence	of	resistant	CRW	populations	under the	more	stringent	definitions	used	hitherto.		Because	more	stringent	definitions	of resistance	have	demonstrably	enabled	resistant	CRW	to	emerge	without	triggering remedial	action	plans, the se	definitions must	be loosened to	enable	more	timely	response at	earlier	stages	of	resistance .		Otherwise, IRM has	little	chance of	stemming	the	tide	of resistant	CRW.

To	this	end, criteria	that	require	demonstration	of	complete	resistance should	be elim inated. CFS	supports	the	first	criterion	of	the	Single	On

- Plant	Assay	Option	2 (White paper,	p.	28) as a	fully	sufficient definition	of	confirmed	resistance.

“ Using	a	single	on

- plant	assay	(e.g.,	Gassmann	et	al.	2011	or	similar methods),	a	corn	rootwor m	population	is	said	to	be	resistant	when: T he percent	survival	observed	of	the	field	population	on	Bt	corn	exceeds	the percent		survival	of	the	susceptible	population	on	Bt	corn	(statistically significant;	P

- value	<0.05) .”

The	second	criterion relates	to average	weight : “ The	average	weight	of	the	survivors	from the	field	populat ion	on	Bt	corn	is	equal	to	(no statistically	significant	difference)	or	greater than	the	average	weight	of	the	susc eptible	colony	on	isoline	corn.“

This second criterion	should	be eliminated	for	several	reasons. First,	as	noted	by EPA, it is not	independent	from	the	first (White	paper,	28

- 29) .		Second, average	larval	weight	has	not

4 More	accurately,	one	sh ould	say	some	unknown	mix	of	actual	resistance	and	fear	of	resistance,	with	use	of chemical	insecticides	to	either	control	resistant	CRW	or	as	a	prophylactic	measure	to	forestall	or	pre vent	the spread	of	resistance.9 been	validated	as	a	measure	of	resistance	(Ibid,	p.	17).		Finally,	to	the	extent	that	weight does	pr ove	to	correlate	with	percent	survival,	the	criterion	demands	a	showing	of	complete resistance,	when	as	argued	above	the	definition	must	include incomplete resistance

.

If EPA does	choose	to	use	either instar	development	or	body	size /weight	as	a	criterion	in resistance	definitions,	it should	only	be	used	as a possible alternative measure to	survival, not	as	an	independent	criterion.		This	is	how	it	appears	to	function in	the	first	criterion	of the	proposed	On

- Plant	Assay	Option	1 :

“ A	statistically	significant	difference	in	measures	of either lethality/mortality or sublethal	effects	(growth/development)	between	the field	population	and	the	control	population	on	Bt	corn”	(White	paper,	p.	28

, emphasis	added ).

In	a	similar	context,	EP A’s	BPPD	IRM	team	recommended	a	definition	of	confirmed resistance to	Cry3Bb1	based	on	a	single	criterion	(survival) :

“On

- plant	assays	with	“suspected	resistant”	field	populations	demonstrate increased	survival	of	field	populations	on	Bt	compared	to	non

- s elected	lab colonies.”	(BPPD	2012,	p.	20).

Likewise,	when	presented	with	a	possible	definition	of	resistance	that	involved	meeting both	of	two	independent	criteria	(LC50	and	proportion	of	root	nodes	destroyed),	the	2002 SAP mentioned	above,	which	included leading	experts	on	Bt	resistance, r ecommended	that meeting	a	single	criterion	sufficed	for	confirmation of	resistance:

“ The	Panel	also	agreed	that	rather	than	require	both	clauses,	either	clause would	be	sufficient	to	demonstrate	confirmed	resistance. ” (SAP	2002,	p df	p

. 66)


### Question	5:	Determining	Remedial	Action	A reas No	comment.


### Question	6:	Containment/Mitigation	of	Resistance The	most	effective	measure s to	mitigate	resistant	CRW	populations	will	be	those	that deny CRW	a	food	source.		I t	is	well	know n	that	CRW	infestations	are much	more	likely

– and more	severe	when	they	occur

– in	continuous	corn.		Indeed,	one	of	many	benefits	of rotating	corn	(e.g.	with	soybeans)	is	to forestall CRW infestations

. 5 Thus,	rotating	away from	corn	to	a	non

- CRW	host	crop	is clearly the most effective mitigation	measure,	and	is especially	important	in	view	of	the	sharp	rise	in	in	acres	planted	to	continuous	corn	over

5 A	corn/soybean	rotation	provides	good protection	against	CRW	in parts of	the	Corn	Belt,	but	is	of	less	value in	areas	( e.g. Illinois	and	Indiana)	where a	rotation

- resistant variant has	become prevalent. However,	even	in these	areas	entomologists	have	recommended	that	growers	“continue	rotatin g	as	a	second	line	of	defense”	to soil	insecticides	and/or	rootworm	active	Bt	toxins	(Michael	Gray,	as	quoted	in	Ruen	(2013)).10 the	past	de cade	(addressed	further	below). EPA	shoul d	consider	mandating	such	crop rotations	as	part	of	remediation	plans.

Any	mitigation	that	involves	continuous	corn	is	of	less	value. But	of	measures	that	involve

corn

- on

- corn,	planting	of	non

- Bt	corn	eliminat es all selection	pressure	for	evolution	of

re sistance	to any rootworm

- active	PIP and is	th us the most	desirable (Porter	et	al	2012)

. This is	particularly	true	given	the	inadequate	refuge	size	requirements	for	all	corn
rootworm

- active	PIPs	( see	section	II. B	below ). Rotation	to	corn that express es a different PIP	or	PIP	combination	should	be	the	last	recommendation.

CFS finds	EPA’s	distinction	between	“hot	spot”	and	“area

- wide”	resistance	somewhat misleading (White	paper, 34

- 36)

. While	probably	not	intended	by	EPA,	t he	labels	suggest that	the	opera tive	distinction	is total	area	infested	with	CRW

– little for	“hot	spot” resistance	and much	more	for	area

- wide	resistance

– and	that	the	former	is thus less problematic	and	merits	less	intervention	than	the	latter.		This	is	not	the	case.

As	EPA	acknowledges, reports	of	unexpected CRW damage	to	Bt	corn	are	rising dramatically,	indicative	of	expanding	resistance (see	section	II. A)

. EPA	finds	that	the most likely	scenario	is evolution	“ in	many	different	hot	spots	simultaneously	from	ubiquitous management	practices	favoring	resistance” (scenario	2) rather	than widespread dispersal of resistant	CRW	from	one	or	a	few	hot	spots	(scenario	1).		As	EPA	concedes,	the	end	result of	these	two	scen arios is	not	likely	to	be	distinguishable;	they	are	merely	different	p aths	to “area

- wide	resistance.”

What	distinguishes these	scenarios is	the	relative	importance	of	the evolution of	resistance versus	the spread of	resistance, once	evolved ,	rather	than t he	geographic	extent	of resistance. EPA	is	probably	right	that	scenario	2	predominates.		Resistance	evolution	is not

a rare,	but rather	a frequent event ,	resulting	in	numerous	“hot	spots”	due	to	“widespread agricultural	practices	employed	across	the	Corn Belt	(i.e.	continual	planting	of	corn	for	feed or	ethanol	production,	lack	of	crop	rotation, etc. )	and	the	non

- high	dose	nature	of	the rootworm	Bt	toxins”	(White	paper,	p.	35). EPA	leaves	out	one	of	the	most	important causative factors,	however,	which is	i ts	own	setting	of	entirely	inadequate	refuge	size requirements for	all	corn	events	expressing	rootworm	PIPs ( see	section	II. B ).

The	“many	little	hot	spots”	mode	of	CRW	resistance	emergence	has	further	implications	not addressed	by	EPA. CRW	adults are	cap able	of	sustained,	high

- altitude	flight,	and	can	take advantage	of	prevailing	winds	and	storm	fronts	to	move	considerable	distances	(Isard	et	al 2004). Extreme	weather	is	becoming	more	common	with	climate	change. All	other	things being	equal,	t he	likelih ood that s torms will transport resistant CRW moderate	to long distance s	increases	with	the geographic range and number	of	hot	spots	across	the	Corn Belt. It	is	greater	with	EPA’s	scenario	2	than	scenario	1.		To illustrate this,	imagine	just	one large	population	of	resistant	CRW	(scenario	1)	vs.	50	hot	spots	scattered	across	the	Corn Belt	(scenario	2),	where	the	total	area	occupied	by	resistant	CRW	is	the	same	in	both scenarios.	The	likelihood	of unusual weather events sprea ding resistant CRW	in	scenario	1 is	small,	equivalent	to	the	probability	that	such	a	weather	event	will	occur	(and	occur	at	the appropriate	CRW	life	stage)	in just	one	area.		In	scenario	2,	the	probability	of	CRW

-11 transporting	weather	events	is	much	greater

– somewhat less than	the sum	of	the probabilities	of	occurrence	in	50	different	areas. 6

Thus, some	proportion	of resistant	CRW	populations	in	numerous confined	areas will	spill beyond	their	local	boundaries	during	extreme	weather,	an	additional	mode	of	r esistance spread	that	EPA	must	consider. Most	importantly,	however, frequent emergence	of resistance	in numerous	localized	areas points	directly to the	glaring	weaknesses	in	the resistance prevention component	of	EPA’s	IRM	plans,	to	which	we	now	turn.



## I I. Comments	on	Issues	Not	Addressed	by	EPA

A. Prevalence	of	CRW	Resistance EPA’s	white	paper	and	charge	questions	focus	narrowly	on	technical	issues	associated	with monitoring	for	resistance	and	give	no	overall	impression	of	the	prevalence	and	seriousness of	the	problem,	which	22	corn	entomologists	recently	told	EPA	requires	action	“with	a sense	of	some	urgency”	(Porter	et	al	2012).		Corn	rootworm	resistance	to	Bt	toxins	has risen	dramatically	in	the	decade	since	the	first	rootworm

- active	Bt	corn	event	was approved	in	2003,	but	precise	data	are	lacking.

EPA	must	make	publically	available	much	more	complete	resistance	monitoring	data	so that	farmers,	extension	agents,	entomologists	and	the	public	are	better	informed	about	the extent	of	CRW	resistance	to	Bt toxins.		The	BPPD’s	reviews	of	monitoring	data	(e.g.	BBPD 2011)	contain	some	useful	information,	but	lack	basic	components	such	as	total	number	of unexpected Bt	corn damage	reports	each	year,	broken	down	by	state	and	county. F uller and	standardized	repor ting	of	such	data is	necessary	to	keep	stakeholders	informed. 7

Monitoring	data	provided	by	Monsanto to	EPA shows	a	clear	trend	of declining susceptibility	to Cry3Bb1	since	2005 (BPPD	2011,	Tables	5	and	6). Entomologists	in Nebraska	have	observed moderate	to	severe	rootworm	damage	to	Cry3Bb1	corn	beginning no	later	than	2008,	and	in	Minnesota	since	2009 (Ibid, p. 5) ,	likely	indicative	of	resistance

. CRW	sampled	from	a	damaged	Bt	field	in	Iowa	in	2009	were	confirmed	as	resistant	in	2011 (Gassmann	e t	al	2011), and	resistant	CRW	have	been	confirmed in	Illinois	as	well	(Gray 2012 ).

Between	2009 and 2012,	there were reports	of	heavy	corn	rootworm	damage	to	Cry3Bb1 corn	in	at	least	23	counties	of	6	states	in	the	Corn	Belt	(NE,	IA,	SD,	MN,	WI,	IL)	(BPPD 2012, p.	2).		The	BPPD	IRM	team	believes	that	these	damaged	Cry3Bb1	fields	may	also	be	due	to Cry3Bb1	resistance.

6 “Somewhat	less	than”	because	weather	patterns	in	different	regions	of	the	Corn	Belt	are	of	course	not entirely	independent.

7 Ironically,	perhaps,	University	of	Illinois	entomologist	Joseph	Spencer	expressed	the	hope that	seed companies would	provide	this	information	to	help	farmers	make	planting	decisions	(see	Smith	201 3 ). Farmers	and	s cientists	should	not	be	dependent	on	the good	will	of	seed	firms	(which in	some	cases have denied	resistance	even	exists,	see	Philpott	2011)	for	this	information.		It	is	EPA’s	responsibility	to	provide	it.12 Figure	above	excerpted	from	BPPD	(2012),	p.	17,	report	dated	Oct.	11,	2012.

Figure	above	excerpted	from	BPPD	(2013c),	p. 21, report	dated	Sept.	26,	2013. New	areas	compared	to	Oct

. 2012	map	above	include	western	KS,	eastern	CO,	central	NE,	western	2/3	of	Iowa

, eastern	Illinois and Oklahoma .		As	noted	in	text, heavy damage	to	Cry3Bb 1	field s also	reported	in	M I and	MT	(not	shown on	map).13 An	update	to	the	aforementioned	report	one	year	later	shows	additional	areas	of	heavy CRW	damage	to	Cry3Bb1	corn	in	several	new	regions	(central	NE,	the	western	2/3	of	Iowa, eastern	Illinois	and	in	two	new	states	(CO	and	KS),	for	8	states	altogeth er	(BPPD	2013c, Figure	5,	p.	21).		Additional	though	apparently	less	frequent	reports	of	unexpected	damage to	Cry3Bb1	corn	came	from	three	additional	states:	Michigan,	Montana	and	Oklahoma (BPPD	2013c,	p.	16).		Thus,	CRW	have	caused	heavy	damage	to	Cry3Bb1 corn	in	at	least	11 states,	and	most	of	these	cases	likely	represent	CRW	that	have	evolved	resistance	to Cry3Bb1.		On	the	preceding	page,	two	maps	are	reproduced	from	the	EPA	reports	cited above	that	portray	this	development.

And	there	are	also	signs	of resistance	evolving	to	the	other	two	commercially	available rootworm	toxins

– Cry34/35Ab1	and	mCry3A

– in	the	form	of	LC50	values	in	field populations	that	substantially	exceed	those	of	control	populations:

“A	number	of	field

- collected	populations	have	sh own	LC 50 s	exceeding	the upper	limit	of	the	95%	confidence	interval	of	the	control	population	(see	data reviewed	in	BPPD	2011,	2012,	2013a,	b,	c),	although	none	of	the	populations have	been	deemed	resistant	by	registrants”	(White	paper,	p.	16) 8

The	rapid	e mergence	of	Cry3Bb1

- resistant	corn	rootworm	throughout	the	Corn	Belt,	and signs	of	evolving	resistance	to	the	other	toxins,	raise	several	serious	questions	for	EPA. First	and	most	obviously,	why	are	EPA’s	IRM	plans	for	corn	rootworm	failing	so dramaticall y	and	so	rapidly?



### B. Deficient	Refuge	Requirements All	of	EPA’s	charge	questions	relate	to	changes	in	the	monitoring	program.		Yet by	far	the most	important	reason for	the	expanding	failure	of	IRM	is	to	be	found	in	the	thoroughly inadequate	refuge	size	that	EPA	has	set	for	rootworm

- active	Bt	corn	events.

All	Bt	corn	hybrids	targeting	corn	rootworm produce	relatively	low	doses	of	Bt	toxin, violating	EPA’s	preferred	h igh

- dose	strategy	that	is	met	by	all	or	most	Bt	events	for	major lepidopteran	pests. EPA guidelines	for	a	high	dose require	that	such Bt	plants	kill ≥ 99.99% of	susceptible target insects	in	the	field (SAP	1998,	pp.	4

- 5) ,	equivalent	to	a	survival	rate	of

≤ 0.01%. The	various	rootworm	Bt	events not	only	do	not	meet	this	standard,	they	do	not even	begin	to	approach	it. The survival	rate of	susceptible	CRW on	corn	expressing Cry3Bb1,	averaged	over	three	studies, is 2.6%,	or	260

- fold	higher	than	the	maximum 0. 01%	survival	rate	that	defines	high

- dose	Bt	events .		Similar	CRW	survival	rates	are	found for corn	expressing	Cry34/35 Ab1 (4.2%)	and	mCry3A	(3.6%) (Tabashnik	&	Gould	2012, Figure	2).

8 BPPD	2011,	2012	and	2013c	are	EPA	reviews	of monitoring	data	and field	reports	on unexpec ted	damage	to Cry3Bb1

- expressing	corn; BPPD	2013a	and	BPPD	2013b	are	similar	reviews	for	Cry34/354Ab1	and	mCry3A corn,	respectively

.14 Th ese high	survival	rate s are	indicative	of nonrecessive	inheritance	of resistance,	which is predicted	to dramatically	acc elerate	evolution	of	resistance	relative	to the	recessive resistance to	Bt toxins	like	Cry1Ab seen	in	lepidopteran	pests	such	as	European	corn	borer. In	fact,	survival	rates	in	this	range	represent	a	worst

- case	scenario	for resistance evolution (Tabashnik	&	Gould	2012, p. 769).

A	large	refuge	is	required	to	compensate	for	the	resistance

- promoting	effects	of	the	low dose s of rootworm

- active	Bt	toxins.		Below,	we	focus	on Cry3Bb1 ,	as	both	the	first
rootworm Bt	toxin	and	the	one	to	which	CRW	resistance	is	most	advanced.		But	similar considerations	apply	to	the	others	as	well	given	th eir	similarly	low dose s

.

I n	2003,	EPA	convened	a	Scientific	Advisory	Panel	(SAP)	to	advise	it	on	insect	resistance management fo r Cry3Bb1

- expressing MON863, the	first	Bt	corn	event	targeting	corn
rootworm .		A	clear majority	of the	SAP	(11	of	14	members) recommended	that	a t	least	a 50%	refuge	be	mandated	for MON863 9 ( Knight	2003 ). Th is	SAP, which	included some	of the	world’s leadin g	experts	on pest	resistance	to	Bt	toxins,	found	that	“modeling	suggested that	a	50%	refuge	would	net	at	least	twice	the	time	to	resist ance	as	the	proposed	20% refuge ” (SAP	2002). EPA	ignored	the SAP’s	recommendation and instead	complied	with Monsanto’s	r equest ,	establishing a	20%	refuge (Knight	2003)

. It	appears	that	EPA	took	this action	on	the	basis	of	information	submitted	to	it	by	Monsanto after the	SAP	meeting	took place	(Pollack	2003),	information	that	was	thus	unavailable	for	critical	review	by	the SAP.

In	contrast	to	Bt	resistance	experts, EPA	claimed	the n	that	it s	modeling projected	that even if	Cry3Bb1

- producing	corn	were	planted	all	over	the	U.S.,	it	would	take	7	to	16	years	for resistance	to	become	a	problem (Knight	2003) :	that	is,	not	until	2 009	to	2018. With	the much less	extensive	plantings	projected	by	Monsanto,	resistance	would presumably take much	longer	to	emerge. As	it	turned	out, MON863	plantings in	fact represented	just	17%	of aggregate	corn	plantings	from	its	introduction	in	2003 to	2009. 10 Despite	this	limited acreage,	resistance	emerged	no	later	than	2009	(Gassmann	et	al	2011),	the	earliest	date that	EPA	had	predicted	for	its	“worst

- case”	scenario	of	nationwide	coverage	with	MON863.

EPA’s	ostensible	reasons	for	acceding	to	Monsa nto’ s	request	for	a	20%	refuge	were: 1) The	registration	being	considered	was	interim,	lasting	only one year with probable	extension	to	three	years	(Pollack	2003) ; and	even	with	a	refuge	as small	as	20%,	resistance	was	not	likely	to	evolve	in	three	years ,	aft er	which time the	refuge size	requirement	could	be	re

- evaluated	and	changes	made	as
necessary (Knight	2003) ; 2) Growers	would	be	confused	by,	and	not	comply	with,	a	refuge	as	large	as	50%, while	their	familiarity	with	a	20%	refuge	(from	Bt corn	targeting	Europ ean	corn

9 A	majority	favored	50%;	a	couple	of	panel	members	supported	a	refuge	of	greater	than	50% (Tabashnik	& Gould	2012,	p.	770)

. 10 Based	on	Monsanto biotechnology	trait	acreage	figures	calculated	from	Monsanto	(2009)	and	USDA	NASS data	on	total	corn	plantings. Cry3Bb1

- expressing	corn comprised 1%,	2%,	5%,	13%,	22%,	35%,	and	36%	of U.S.	corn	plantings	from	2003	to	2009,	respective ly

.15 borer)	would	increase	compliance (SAP	2002 ,	pdf	p. 58,	expressing	the	views	of a	minority	of	SAP	members,	3	of	14)

. In	making	the se argument s ,	EPA	essentially	ignored the	majority	of its	scientific	advisers, who “concluded	th at	there	was	no practical	or	scientific justification	for	establishing	a precedent	for	a	20%	refuge” f or	MON863 (SAP	2002

, pdf	p

. 57, emphasis	added )

.

As	for EPA’s	first	reason, the	SAP warned	that while	the	20%	refuge	was	not	likely	to	result in	field	fa ilures	due	to	resistance	during	this	three

- year	period:

“[i]t	could,	particularly	in	local	areas,	lead	to	a	significant	increase	in resistance	allele	frequencies	over	this	time.		This	increased	frequency	would limit	future	options	for	resistance	managemen t	relative	to	Cry3Bb1	and	any other	toxin	for	which	there	was	cross

- resistance	with	Cry3Bb1. Panel members	indicated	that	the	choice	of	a	20%	refuge	for	the	interim	plan	was likely	to	limit	choices	of	refuge	size	in	the	future	because	farmers	and companie s	would	not	desir e	to	increase	refuge	size. ” (SAP	2002,	pdf	p.	57)

The	SAP ’s	majority was	correct	on	both scientific	and	practical	grounds

. As	noted	above, CRW	s urvival	rates and/or the amount	of	toxin	required	to	kill	or	impair	growth have generally	increased	over	time	for	all	of	the	rootworm

- active	Bt	toxins,	including	Cry3Bb1, indicating	a	rise	i n	resistance	allele	frequency.		A	50%	refuge	would	have	diluted	resistance genes	and	delayed	resistance	much	better	than	the	unscientific	20% refuge	that	EPA actually	implemented. As	noted	above ,	the	SAP	found	that	a	50%	refuge	would have	at least	doubled	the	time	to	emergence	of	resistance	relative	to	the 20%	refuge.

Neither	did	EPA (to	the	best	of	our	knowledge) make	any	attempt	to	re

- asses s	its	interim decision	or	increase refuge	size	at any	of	the	three	decision	points	on extending	the registration	of Cry3Bb1

- expressing	corn	(MON863	or	its	successor	MON88017) in	2004, 2006	or	2010. 11

EPA	presented	no	empirical	evidence	in	support	of	its	se cond reason regarding	grower compliance ,	while	ignoring	evidence that	undermined	it.		First	of	all,	in	the	five	years preceding	introduction	of	MON863, U.S. corn	farmers	applied	insecticides	to	control	CRW on	just	1 4	to	18	million acres	of	corn	each	year

, representing	18%	to	23%	of	total	corn acres	(EPA	2005). If	CRW	infestation s justified	spraying	on	just	one

- fifth	of	national	corn acres,	it	is	difficult	to	understand	how	permitting	50%	of	corn (over	twice	as	much) to	be “treated”	with	Cry3Bb1 would	resul t	in	massive	non

- compliance	with	a	50%	refuge requirement. 12

11 The	EPA	initially	(2/24/03)	issued	a	time

- limited	registration	for	MON863	corn	that	was	renewed	for	two years	on	4/23/04;	then	for	four	additional	years	on	7/27/06.		In	September	2010,	the	registration	for MON863 ’s successor , MON88017
, was	extended	for	five	years	and	now	expires	on	9/30/15	(EPA	2010 a , Regulatory	History,	pp.	9

- 18).

12 While	the	proportion	of	corn	acres	sprayed	for	CRW	would of	course vary	greatly	at	the	on

- farm	level depending	on	CRW	pressure	in	various	regions,	the	fact that	only	20%	of	corn	acres	were	sprayed	for	CRW nationally	suggests at	least	that	the	pest afflicts	a	clear	minority	of	corn	at	economic	injury	levels in	any	give n16 Second,	EPA	completely ignored the	precedent	of	insect	resistant	management	(IRM)	for	Bt cotton	in	Australia ,	which	was	discussed	and	cited	as	a	precedent	by	the	SAP	(SAP	2002, pdf	pp.	57

- 58) .		There,	government	regulators successfully implemented

, and	farmers complied	with

, a	comprehensive IRM plan	tha t	included a 50%	refuge	requirement and involved a	host	of other	measures	as	well (Fitt	2004,	Table	1	and	p.	17) :
1) Sliding	cap	on	the	proportio n	of	national	cotton	acreage	that	could	be	planted	to single

- toxin	(Cry1Ac)	cotton,	which increased in	stages from just 8%	in	1996/97 to	a	maximum	of	30%	in	2001/02; 13 2) Refuge	requirements stipulating that	up	to	50%	of	a Bt	cotton farmer’s	fields	be planted to non

- Bt cotton; 14 3) Defined	planting	window	to	avoid	late	planted	cotton	that	could	serve	as	host	for H.	armigera late	in	the	season; 4) Mandatory	cultivation	of	Bt	cotton	to	destroy	overwintering	pupae	of H. armigera and	mandatory	removal	of	volunteer	Bt	plan ts	in	subsequent	seasons; 5) Three	audits	per	year	for	each	farm	growing	Bt	cotton	to	check	on	compliance with	refuges;	among	other	requirements	(Fitt	2004).

Australian	regulators	established this stringent IRM	plan because

, vis

- a

- vi s the	chief Australian	co tton	pest	( H.	armigera )	“Inguard	cotton	varieties	expressing	a	single Cry1Ac gene	clearly	do	not	express	a	high	dose	and	heterozygote	mortality	is	unlikely	to	be	high except	perhaps	when	plants	are	quite	young...”	(Fitt	2004). This	mirrors	precisely	the sit uation	EPA	faced	with	MON863 and	corn	rootworm .		While	Australian	regulators followed	the	science	and	have	thus	far	succeeded	admirably	in	forestalling	resistance,	EPA rejected	the	science	in	favor	of	entirely	unfounded	speculation	about putative	farmer	no n

compliance and	thus set	the	stage	for	today’s	rapidly	emerging	CRW	resistance.

As	the	reports	of	unexpected	damage	to	Cry3Bb1	corn	and	hence	the	incidence	of	CRW resistance	escalate,	EPA	has	responded, incredibly ,	by sharply reducing the	already inadequate	20%	refuge	requirement.		EPA’s	rationales	for	doing	so

– refuge	in	a	bag	and pyramided	Bt	corn	products

– have	no	more	scientific	merit	than	its	decision	to	set	a	20% refuge

. Refuge	in	a	bag	(RIB) or	blended	refuge is	a	seed	mixture in	which	the	non

- Bt seed 15 is mixed	together	with	the	Bt	seed;	the	“refuge”	is	then	comprised	of	the	non

- Bt	corn	plants

year; and	that	constraining the	minority	of corn	farmers with	economic	CRW	infestations to plant	half	their fields	to	non

- Cry3Bb1	corn	would	have	been	a	reasonable	requirement	striking	a	scientifically	sound	balance between	current	benefits and	long

- term	sustainability

. 13 Australian	regulators	worked	with	industry	to	orchestrate	a	planned	tran sition	from	single

- toxin	Cry1Ac cotton	to	dual

- toxin	Bollgard	II	cotton,	which	took	place	in	the	2003/04	season,	the	only	season	in	which	both single	and	dual

- toxin	varieties	were	planted. The	national	cap	was	eliminated	at	this	time,	though	other	IRM

meas ures	remained	in	effect.

14 Refuge	requirements	varied	by refuge crop	and	management	practice.		A	refuge	of	50%	was	required	if	the

non

- Bt	cotton	refuge	was	sprayed	for	CRW. Refugia	could	be	smaller	if	unsprayed.17 growing	uniformly	intermixed	with	the	Bt	plants .		The	other	form	of	refuge	is	the	block	or structured	refuge,	where	the	non

- Bt	plants	ar e	planted	together	in	a	plot	or	plots	adjacent to	the	Bt	corn. EPA required	block	refugia	for	all	Bt	crop	varieties	until	2010,	when	it registered	the	first	refuge	in	a	bag	product,	Optimum	AcreMax,	which	consisted	of	90% Cry34/35Ab1	and	10%	non

- rootworm Bt	corn	(EPA	2010b). This	90:10	ratio	for	RIB represented half	the	refuge required	for	the	same	Cry34/35Ab1	corn in	a structured
context ,	where	a	20%	refuge	is	required.

Once	again,	EPA’s	decision was	directly	contrary	to	the	recommendation	of	its	expert advisors. A	Scientific	Advisory	Panel convened	to	advise	EPA	on	this	very	question	was unequivocal:	“The	Panel	generally	agreed	that	data	presented	by	Pioneer	and	data	found	in the	public	literature	provide	no	compelling	evidence	to	reduce	the	proportion of	non

- Bt plants	(either	as	a	seed	blend	or	spatial	refuge)	from	20%....”	(SAP	2009,	p. 6).		“[I ]n	fact, the	Panel	recommended	that	the	proportion	of	non

- Bt	plants	remain	at	20%	rather than	be	reduced	to	10%	as	proposed	by	BPPD .		The	recommendation	from	a previous FIFRA	Scientific	Advisory	Panel	was	for	a	50%	refuge. ”	(SAP	2009,	p.	21,	emphasis added).

The experts	on	this	Scientific	Advisory	Panel	were	not	alone. Most agronomists	and entomologists	see	refuge	in	a	bag	as	a	decidedly	“mixed	bag”	that	has	s ome	advantages over	the	traditional	block	refu ge	as	well	as	some	disadvantages.		Thirteen	agronomists	who evaluated	the	issue	found	that	“neither	blocks	nor	refuges	are	clearly	superior” (Onstad	et al	2011 ;	see Table	1	from	that	paper,	reproduced	below),	m aking	it	very	unclear	whether RIB	justifies	any	reduction	in	refuge	size	at	all.		What	is	clear,	however,	is	that	any effect that	RIB might have	in delaying	resistance	should	not	be	undercut	by	slashing	the	refuge size,	given	the	continuing	rapid	emergence of	CRW	resistance	throughout	the	U.S.

Pyramided	Bt	products	incorporate	two	or	more	Bt toxins	that	act	on	the	target	pest(s) with	differing	modes	of	action,	thereby	reducing	the	likelihood	of	resistance	evolving	to either	one.		In	2009	and	2011,	EPA	registered	Cry3Bb1	+	Cry34/Cry35Ab1	corn	and mCry3A	+	Cry34/Cry35Ab1	corn,	respectively.		Fo r	these	products,	EPA	slashed	the prevailing	20%	refuge	requirement	for	single

- toxin	Bt	seed	by	75%,	from	20%	to	just	5% (Tabashnik	&	Gould	2012,	Table	1).

15 As	used	here,	“non

- Bt seed”	means	seed	that	does	not	contain	a	rootworm

- active	Bt	toxin;	it	may	be	either conventional	seed	or	contain	one	or	more	Bt	toxins	targeting	lepidopteran	pests.18 Source :	Onstad	et	al	(2011).

Similar	arguments	apply	here	as to refuge	in	a	bag	(even	though pyramids more	clearly provide a t	least	a	modest resistance	prevention	boost versus RIB). With	resistance	to Cry3Bb1	on	the	rise	due	to	a	clearly	inadequate 20% refuge,	it was	reckless	of	EPA to squander	the	resistance

- fighting	effects	of	the	pyramid	through a	resistance

- promot ing reduction	in	refuge	size.		The	first	pyramid	cited	above	acts	as	a	single

- toxin	product	for	the large and	growing number	of	CRW	that are	rapidly	evolving resistance	to	Cry3Bb 1 throughout	the Corn	Belt.		In	those	resistance

- ridden	ar ea s where	this	pyramid	is most likely	to	be grown, there	is	next	to	no	refuge	corn	(only	5%)	to	dilute the Cry34/35 Ab1 resistance	alleles	that	can	be	expected	to	rapidly	accumulate	in	Cry3Bb1

- resistant	CRW. The	expected	result	is	rapid	evolution	of	CRW	re sistant	to	both	toxins.

The	situation may	be somewhat better	for	the	second	pyramid, but	rather	uncertain due	to the close amino	acid	sequence similarity	and likely cross

- resistan ce	between	Cry3Bb1	and mCry3A.		Only	time	will	tell	the	magnitude	of	the	cro ss

- resistance	risk.		If	it	is	small,	then this	pyramid has	the	potential	to	be more durable;	if	on	the	other	hand	resistance	to Cry3Bb1 frequently	confers	resistance	to mCry3A (and	vice	versa )

, then similarly	to the first	pyramid

, an	increasing	number	of	C RW	already	resistant	to the Cry3 toxins will experience	intense	selection	pressure to	evolve additional	resistance	to	Cry34/35 Ab1

.

EPA’s BPPD IRM	team	summarizes	the	situation	well:

“BPPD is	concerned	with	these	preliminary	reports	of	cross

- resistance between	Cry3Bb1	and	mCry3A	and	the	planting	of	CRW	pyramided	corn expressing	Cry3

- Bt	toxins	in	areas	with	Cry3Bb1	resistant	corn	rootworm populations. Such	pyramids	are	effectively	reduced	to a	single	toxin product	deployed	with	a	much	lower	refuge	(5%). There	are	currently four	registered	corn	rootworm	toxins,	two	of	which	(mCry3A	and	Cry3Bb1)19 would	be	ineffective	in	corn	rootworm	resistant	areas. The	selection pressure	in	these	regions	on the	remaining	toxin,	Cry34/35,	will	be tremendous	if	deployed	in	a	pyramid	with	Cry3Bb1	and	a	reduced	refuge of	5%.” (BPPD	2013c,	p.	24 ,	emphasis	added )

It	is also concerning	that	the	Cry3Bb1	+	Cry34/Cry35Ab1	pyramid	(sold	commercially	as SmartStax)	does not	have	anywhere	near	the	lethality	that	one	would	expect	if	the	two toxins	acted	independently.		The	predicted	survival	rate	assuming	independent	action	is just	0.145%;	yet	the	observed	survival	rate	is	12	times	that,	or	1.8%

, ≥ 180	times	the

≤ 0.01%	surv ival	rate	that	defines	a	high

- dose	event (Tabashnik	&	Gould	2012).		The	fact that	the	SmartStax	pyramid	delivers	only	a	marginally	higher	dose	than	its	constituent single

- toxins ,	and	is	still	a	low

- dose	event, represents another	argument	against	EPA’s irre sponsible	reduction	in	refuge	requirements	to	a	miniscule	5%.

In	light	of	these	and	similar	considerations,	two	of	the	world’s	leading	experts	on	Bt resistance,	Drs.	Bruce	Tabashnik	and	Fred	Gould, recently recommend ed that	EPA	establish a	50%	refuge	for all	single

- toxin	Bt	corn	products,	and	a	20%	refuge	for	pyramided products (Tabashnik	&	Gould	2012) .		These	sensible	recommendations

– which	logically propose	that increasing CRW	resistance	be	countered	by strengthening IRM

– is thoroughly	at	odds	with	EPA ’s inexplicable actions	that	dramatically weaken it

. If	short supplies	of	non

- Bt	seed	make	immediate	establishment	of	these	refugia requirement s unworkable, increases	in	refuge percentage could	be	phased	in	over	years	to	give	seed firms	time	to	multiply	the	needed	seeds.



### C. Declining	Availability	of	High

- Q uality Conventional	(Non

- Bt)	Corn E ndangers	IRM The	discussion	above suggests that	a n	adequate	supply	of	high

- quality,	non

- Bt	corn seed is an	indispensible	element	of	any	successful	IRM	p lan.		With	a	large	majority of	U.S.	corn acreage	planted	to	varieties	with	Bt	toxins (76%	in	2013)

, 16 refugia	represent	by	far	the biggest	source	of	demand	for	non

- Bt	corn	seed	today.		An	indirect	effe ct	of	EPA’s reckless slashing	of	refuge	requirements	is	a	corresponding	decline	in	demand	for non

- Bt	corn seed

, a ccompanied	by	a reduction	in	the	diver sity
, quality and	volume of non

- Bt offerings

. The paucity	of	non

- Bt	corn	seed	in	turn	undermines	integra ted	pest	management (IPM). Growers	who	would	like	to periodically	grow conventional corn as	part	of	their	overall	IPM strategy find	it	increasingly	hard	to	do so. IRM	is	reduced	to	a	dangerously	narrow	set	of transgenic	options: switching	among different	Bt	modes	of	action	or	(more	commonly) combining	them	in	pyramids (Gray	2011)

.
Numerous	agronomists have	warned	of	the se intertwined problems	of	declining availability	of	non

- Bt	seed	and	the	demise	of	IPM. In	a	2010	survey,	University	of	Illino is

16 Up	sharply	from	67%	in	2012,	likely	reflecting	the	increased	use	of	RIB	with	5%

- 10%	refu ge	requirements. See http://www.ers.usda.gov/data

- products/adoption

- of

- genetically

- engineered

- crops

- in

- the

us.aspx#.Upyxd6VXaa4 .		Add	figures	for	“insect

- resistant”	and	“stacked”	corn	(stacked	corn	by	definition includes	traits	for	both	herbicide

- and	insect

- resistance).20 entomologist	Michael	Gray	found	that	fully	40%	of	Illinois	corn	farmers	did	not	have	access to	elite	varieties	of	non

- Bt	corn	seed	in	2009	(Gray	2011,	Table	2). Onstad	et	al	(2011) also find that	the	pool	of	nontransgenic	corn	hybrids	is	shrinking,	giv ing	growers	fewer	choices to	eliminate	selection	pressure	by	growing	conventional	corn

.
Twenty

- two public	sector	corn entomologists ,	many	with	extension	responsibilities	and hence	familiarity	with the	challenges	farmers	face

, w arned EPA	that declining	av ailability	of high

- yielding non

- Bt	corn varieties leads	to	prophylactic	or	entirely	superfluous deployment	of	Bt	toxins,	and hence needless	selection	pressure	for	resistance .		This	in	turn erod es an	essential	tool	in	the	fight	against	further evolution	of CRW	resistance to	Bt toxins :

“Rootworm

- protected	Bt	corn	is	being used	prophylactically	in	areas	with	little	or no	need	for	it. This unwarranted	use occurs	in	part	because	genes	to	produce rootworm	Bt	toxins	(and	toxins	active	against	Lepidoptera)	are	in corporated	into elite	germplasm	with	the	highest	yield	potential.		Thus	growers	often	have	few options	other	than	to	plant	stack s	and	pyramid s	if	they	wish	to	use	the	hybrids	with best	yield	potential.		When	growers	do	not	want	to	use	Bt	corn,	many	report increasing	difficulty	in	obtaining	non

- transgenic	seed. Scarcity	of	non

- Bt	seed	may become	more	acute	as	the	seed	industry	transitions	to	a	refuge	“in	the	bag” approach	for	resistance	management.

Planting	non

- Bt corn	can	be	profitable	and	should	be	one	of	the	IPM	tools	to maintain	susceptibility	to	rootworm

- protected	transgenic	corn. After	all, whether	used	in	conjunction	with	soil

- applied	insecticides	or	not,	conventional hybrids	cause	no	selection	for	resistan ce	to	any	Bt	toxin.		It	is	ironic	that the decreasing	availability	of	non

- Bt	hybrids	erodes	the	ability	of	producers	to	move to	a	more	integrated	system	of	corn	rootworm	management,	one	that	protects the	value	of	Bt	hybrids .		As	a	component	of	effective	IP M	for	corn	rootworms, attention	should	be	given	to	increasing	the	supply	of	elite hybrids	that	do	not contain	Bt ” (Porter	et	al	2012,	emphasi s	added)

It	is	noteworthy	that	“refuge	in	a	bag,”	an	innovation	that	EPA	has	used	to	justify the refuge reduction s	( e.g. 20% block to 10% RIB	for Cry34/35Ab1	corn)	desired	by	industry,	is	cited by	these	corn	entomologists	as	a	prime	driver	of	non

- Bt	corn	scarcity
, and	hence superfluous selection	pressure that	accelerates CRW	resistance	to	rootworm	toxins. Gray (2011 )	makes	a	similar	point.

Thus,	EPA’s	unjustified	reductions	in refuge	requirements	exacerbate rootworm	resistance in	two	ways:	1)	Directly,	by	shrinking	the	pool	of	susceptible	insects	for	dilution	of resistance	alleles;	and	2)	Indirectly,	by	reducing	dem and	for non

- Bt	corn ,	which	leads	to declining	availability	and	planting	of	non

- Bt	seeds	that	are	urgently	needed	to	less en selection	pressure	for	rootworm	resistance	to	Bt	toxins.

Monsanto	wanted	a	20%	rather	than	a	50%	refuge	requirement	because its	ma kes	more profit	selling	biotech vs.	conventional	seeds ;	and	seeds	with	more	vs.	fewer	traits. Related to	this,	the	20%	refuge	requirement	matched	the	existing	one	for	Bt	corn	targeting21 lepidopteran pests.		Having	the	same	refuge	requirements	for	rootworm	and	lepidopteran Bt	corn	greatly	facilitated	Monsanto’s profit

- driven “biotech	trait	penetration”	strategy	of combining	both	Bt	traits	in the great majority of	their	corn	varieties,	and sharply	redu cing single	Bt offerings of	either	sort. This	trend	is	reflected	in Monsanto’s	biotechnology	trait acreage	figures ,	which	show	that U.S. acreage	planted	to	Monsanto	single

- Bt	corn (of	either sort) peaked	at	34	million	acres	in	2004,	declining	to	7.9	milli on	acres	by	2009;	while plantings	of Bt	corn targeting	both	CRW	and	lepidopteran	pests increased	from 0 to	31.3 million	acres	over	the	same	period	(Monsanto	2009).

I f	EPA	had	followed	the	science	and	established	a	50%	refuge	requirement,	it	would not only have	dramatically	slowed	evolution	of	resistance.		It	would have	had	the	additional beneficial	effect s of	encouraging	Monsanto (and	other	seed	firms) to	offer more conventional and /or more	single

- toxin

- Bt corn	lines. 17 This	increased	diversity	of	seed off erings	would	have	better	met	fa r mers’	needs	and	reduced	the	“unwarranted	use”	of	Bt toxins mentioned	above by	farmers	who are	presently	constrained	to	buy	them	even though	they have	no agronomic need	for	them.

Industry	and	EPA	often	place	the	blame	for	re sistance	on	farmers	for not	always complying with	refuge	requirements.		The	analysis	presented	above	suggests	that	seed	firms are as	or more	culpable

. F armer	non

- compliance	with	refuge	requirements is at	least	partly attributable	to	the	dearth	of	locally adapted,	high

- yielding	conventional	(non

- Bt)	varieties on	offer

. 18



### D. Increasing	Corn	Monoculture U.S.	c orn	acreage	has	increased	a	substantial	31%	since	1990,	to	a	near	historical	high	of 96.9	million	acres	in	2012.		The	19%	increase	in	corn	acreage	since	the	year	2005	in particular	is	attributable	largely	to	ethanol	demand, which	has driven	up	corn	prices and made	corn more	profitable	to	grow	than	most	other	crops.		The portion	of	U.S.	corn production	utilized	for	ethanol	rose	from	just	14%	in	2005	to roughly 4 0 %	in	2012. This rise	in	overall	corn	acreage	has	meant	more	acres	planted	to	cor n	continuously, year	after
year

. A	recent	assessment	that	utilized	satellite	imagery	to	determine	cropping	patterns	in	the central	U.S.	found	that	corn	monoculture	has	increased	sharply	over	the	past	decade (Plourde	et	al	2013) .		From	2003	to	2010,	the	land	area	planted to	corn	two	years	in	a	row increased	by	22%. Still	more	striking,	t he	amount	of	corn	in	quadruple	planting	(four	years of	corn	in	a	row)	doubled

– from	4%	to	8%	of	total	corn	acres

– from	the	first	half	of	the period	2003

- 2006	to	the	second	half	of	the	20 07

- 2010	time	period.

17 Especially	single

- toxin	Bt	for	lepidopteran	pests,	since	these	could	be	used	to	meet	the	50%	refuge requireme nt	and	would	be	more	profitable	than	conventional	lines.

18 A	related	reason	for	non

- compliance has	been farmer	anticipation	of	refuge

- in

- a

- bag,	which	led many to believe	that	structured	refuge	requirements (and	hence	compliance	with	them) w ere of	little	i mportance, since	soon	to	be	replaced	by	RIB	(Gray	2011).22 Cultivation	of	corn	continuously	on	the	same	fields over	years	is	associated	with several adverse	impacts	relative	to	corn	grown	in	rotation	(e.g.	with	soybeans):	lower	yield ; higher per	acre	fertilizer	use	in	an	attempt	t o	compensate for	reduced	yield; greater	disease
pressure ; corn	rootworm	infestations;	and,	if	the	corn	expresses	a	rootworm

- active	Bt toxin,	accelerated	evolution	of	resistance.

Nearly	all	reports	of	Cry3Bb1

- resistant	CRW	have	been	in	fields	planted	continuously	to Cry3Bb1

- producing	corn.		For	instance,	the	first	published	paper	on	resistant	CRW (collected	in	2009)	noted	that	all	fields	harboring	them	had	been	planted	to	Cry3Bb1	corn for	at	least	three	consecutive	years:

“In	all	cases,	fields	experiencing	severe	roo tworm	feeding	contained	Cry3Bb1 maize.	Interviews	with	farmers	indicated	that	Cry3Bb1	maize	had	been grown	in	those	fields	for	at	least	three	consecutive	years.	There	was	a significant	positive	correlation	between	the	number	of	years	Cry3Bb1	maize had	been grown	in	a	field	and	the	survival	of	rootworm	population s	on Cry3Bb1	maize	in	bioassays.”	(Gassmann	et	al	2011)

The	same	team	found	that	2010	CRW	populations	determined	to	be	resistant	“came	from fields	with	a	history	of	continuous	maize	production	and	b etween	3	and	7	years	of	Cry3Bb1 maize	cultivation”	(Gassmann	et	al	2012).

While	continuous	corn	is	nothing	new, it	has	always	represented	a	minority	of	corn	acres. M ost	fa rmers	have	been	reluctant	to	plant	corn	in	successive	years	because	of	the heighten ed	risk	o f	rootworm	infestations and	the	other	problems	mentioned	above: reduced	yield,	greater	fertilizer	use,	and	disease	issues. Bt	corn targeting corn	rootworm has been	a	major	factor	in	eroding that	reluctance,	and thus	an	important factor facilitating the	rise	of	corn

- on

- corn discussed above

. 19 Understanding	this	dynamic,	seed	firms	have actively promoted	Bt	corn	for	this	use.

According	to	Wyffels	Seed	Company:

“With	the	advent	of	seed	technology	that	puts	rootworm	protection	in	the plant ,	growing	corn

- on

- corn	has	become	much	easier.		Selecting	hybrids with	Agrisure®	3000GT,	Herculex®	XTRA,	Genuity®	SmartStax®, Genuity®	VT	Triple	PRO®	or	YieldGard	VT	Triple®	technologies	is	a	great way	to	go. ” 20 (Wyffels	Hybrids	undated)

Monsanto	goes	so	f ar	as	to	offer	farmers	“Corn

- On

- Corn	Clinics

, ” which	it	describes	as follows:

19 While ethanol	is driving the	demand	for	more	corn	and	hence	more	continuous corn	by	driving	up	corn prices, some	and	perhaps	many	farmers	who did	in	fact	transition	to	“corn

- on

- corn” would	not	have done	so because	of	the	associated	risk	of	major	losses	from	CRW	infestations	if	they	had	not	had	access	to	a	tool	(Bt corn	for	rootworm)	that	for	a	time	at	least	prevented those losses.

20 h ttp://www.wyffels.com/agronomy/continuous

- corn/ ,	last	visited	12/3/13.23 “The	Corn

- On

- Corn	Clinics	are	a	series	of	events	across	the	country featuring	a	panel	of	industry	experts,	academics	and	local	growers	speaking on	a	variety	of	corn	topics,	including	fertility	management,	insect management,	disease	management	and	residue	m anagement. Control	pests in	your	corn

- on - corn	acres	with	the	help	of Genuity ® SmartStax ® RIB Complete TM” corn	blend.” (emphasis	added) 21

Monsanto understands	that	most	growers	have	reservations	about	continuous	corn.		Those reservations	are eroded by	holding	“clinics” in	which	experts	from	Monsanto	and	academia persuade	these	farmers	that	with	proper “scientific” management, corn

- on

- corn can	be good	or	at	least acceptable	agronomic	practice,	when	of	course	there	are	few	practices

more agronomically or environmentally	detrimental. 22 The	chief	facilitator	of	continuous corn	is	Bt	seed

– in	this	case,	SmartStax ,	which is	Monsanto’s	most	expensive	and	profitable product. Monsanto	even	entices	farmers	to	attend	its	“Corn

- On

- Corn	Clinics”	by	offering
atte ndees	the	chance	at	a	$500	gift	card.

Interestingly,	Monsanto’s	2012	“corn

- on

- corn	clinics”	were	all	held	in	areas	where	CRW resistance	to	Monsanto’s	Cry3Bb1	is	prevalent	(see	map	on	next	page),	and	thus	where SmartStax	often	acts	as	a	single

- toxin	produc t	with	a	paltry	5%	refuge.		There	is	no	better recipe	for	rapid	evolution	of	resistance	to	the	sole	Bt	toxin	that	(at	present)	remains	largely uncompromised	(Cry34/35Ab1).

21 http://www.genuity.com/corn/Pages/Corn

- on

- Corn

- Clinics.aspx ,	last	visited	12/3/13.

22 Aside	from	fostering	CRW,	increased	acreage	planted	to	continuous	corn	is	likely	a	major	factor	in	the record	rates	of	inorganic	nitrogen	fertilizer	applied	to	corn,	since	as	noted	above	N	use	is	normally	boosted	in continuous	corn	to	compensate	for	reduc ed	yield	relative	to	corn in	a	corn/ soybean rotation .		In	2010,	the last	year	for	which	USDA	data	are	available,	an	average	of	140	lbs./acre	of	nitrogen	fertilizer	w ere applied	to corn,	the	highest	rate	since	1964	(although	matched	in	1985).		See	“Table	10 .		Nitrogen	used	on	corn,	rate	per fertilized	acre	receiving	nitrogen,	selected	States,”	accessible	from: http://www.ers.usda.gov/data

products/fertiliz er

- use

- and

- price.aspx#.Up40LqVXaa4.n .		Corn	is	by	far	the	biggest	N	using	crop,	and	N	runoff generates	dead	zones	in	coastal	waters	while	N	fertilizer	also	contributed	substantially	to	global	warming through	conversion	to	nitrous	oxides,	potent	greenhouse gases.24 Figure	5. 2013	Updat ed	map	showing	the	general	areas	in	the	US	Corn	Belt	that	have	had	Cry3Bb1	fields	with heavy	damage	and/or	resistant	western	corn	rootworm	populations	(2009

- 2012)

. Map	excerpted	f rom	BPPD (2013c). CFS	has	amended EPA’s map to	show	(in	red)	towns	in	wh ich	Monsanto	gave	“corn

- on

- corn	clinics” in	the	summer	of	2012. See http://www.genuity.com/corn/Pages/Corn

- on

- Corn

- Clinics.aspx

.



### E. Volunteer	Herbicide

- Resistant	Corn Volunteers	are	crop	plants	that	sprout	from	unharvested	seed	to	infest	the	following season’s	crop	grown	on	the	same	field.		Harvesting	equipment	always	leaves	some proportion	of	the	crop	seed	in	the	field.		For	instance,	storms	and	plant	disease	often	cau se corn	plants	to	topple,	leading	to	ears	of	corn	on	or	near	the	ground	that	are	then	missed	by harvesters.		Some	proportion	of	this	seed	will	find	conducive	conditions	to	sprout,	so	some level	of	volunteer	presence	is	an	inescapable	fact	of	farming.		Corn volunteers	can	be	a troublesome	weed	in	the	following	season’s	crop,	especially	soybeans,	dry	beans,	sugar beets	and	subsequent	corn	crops	(Bernards	et	al,	2010;	Davis,	2009;	Johnson	et	al,	2010; Stewart,	2011).		Two	to	four	volunteer	corn	plants	per	squa re	meter	can	reduce	yields	in soybeans	by	20%	(Morrison	2012).

Volunteer	corn	not	only	reduces	yields,	it	can	act	as	a	host	plant	for	corn	rootworm	in	years when	corn	is	not	grown.		In	the	common	corn/soybean	rotation,	volunteer	corn	provides	a bridge	f or	rootworm	populations	to	persist	in	the	soybean	years.		If	the	volunteer	corn	is	Bt Burlington,	CO Norfolk,	NE Spencer,	IA

Cascade,	IA25 for	CRW,	it	could	also	acceler ate	the	evolution	of	resistance,	especially	when	stacked	with an	herbicide	resistance	trait.

Krupke	et	al	(2009)	examined	volunteers	of	sta cked	glyphosate

- resistant/insect

- resistant corn	emerging	in	follow

- on	glyphosate

- resistant	soybeans.		They	found	that	65%	of	the volunteers	tested	positive	for	Cry 3 Bb1,	and	that	60%	tested	positive	for	both	glyphosate

resistance	and	Cry 3 Bb1.		Surprisingly, Cry 3 Bb1

- positive	corn	volunteers	exhibited	the same	degree	of	root	damage	from	larval	rootworm	feeding	as	volunteers	that	tested negative	for	the	Cry 3 Bb1.		They	hypothesized	that	these	volunteers	produce	lower,	non

lethal	levels	of	Cry 3 Bb1	due	to	deficien t	nitrogen	in	soybean	fields	that	are	not	amended with	this	nutrient (as	corn	fields	are)

. Whatever	the	reason,	e xposure	of	corn	rootworm	to low	levels	of	Cry3Bb1	in	corn	volunteers has likely	accelerate d evolution	of	resistance	and helped undermin e insec t	resistance	management	efforts.

Corn	volunteers	have	become	an	increasingly	problematic	weed	in	their	research	area (Indiana)	and	throughout	the	Corn	Belt	because	glyphosate

- only	weed	control	programs with	Roundup	Ready	soybeans	fail	to	control	glyphosat e

- resistant/Bt	corn	volunteers	in common	soy/corn	rotations.		Krupke	et	al	conclude	that	“weedy	volunteer	corn	plants stacked	with	GR	[glyphosate

- resistance]	and	Bt	traits	may	accelerate	the	development	of Bt

- resistant	WCR	[western	corn	rootworm]	populatio ns,	circumventing	the	current	[Bt insect

- resistance]	management	plans.” In	continuous GR/Bt corn managed	with glyphosate ,	G R/Bt	corn	volunteers	producing	lower,	resistance

- promoting	levels	of rootworm	toxin	would	be	still	more	likely	to	escape	control tha n	in	soybeans ,	since	harder to	distinguish	as	volunteers	in	a	field	of	corn.

In	2013,	only	5%	of	U.S.	corn	acres	were	Bt	only,	versus	71%	stacked	with	both	Bt	and herbicide	resistance, 23 giving	a	sense	of	the	scope	of	this	problem.		And the CRW	resistance risks	posed	by	volunteer	corn will	only	increase	with	the	introduction	of	multiple herbicide

- resistant /Bt corn	varieties that	are	still	more	difficult	to	control	than	those	with the Roundup	Ready trait	alone. Already,	SmartStax	corn	volunteers	(which	inco rporate both	glyphosate	and	glufosinate	resistance)	have	been	noted as	more	problematic	weeds than	G R	corn	volunteers,	especially	in	corn

- on

- corn	rotations	(Brooks	2012,	Morrison 2012). R ecommended	control	practices	for	such	dual

- HR	corn	volunteers	are	a pre

emergence	application	of	a	paraquat

- atrazine	mixture,	or	post

- emergen ce	use	of	inter

- row cultivation	(USDA	APHIS	2013,	p.	37).		Neither	paraquat	(applied	to	just	1%	of	corn	acres	in 2010 24 )	nor	inter

- row	cultivation	are	used	much	in	corn;	thus	many	grow ers	would	likely leave	such	volunteers	uncontrolled.

Dow	AgrosSciences	is	awaiting	deregulation	of	GE	corn	resistant	to	2,4

- D	and “fops” grass herbicides ,	which	would	be	stacked	with	glyphosate

- resistance

. 25 Monsanto	is	developing

23 See http://www.ers.usda.gov/data

- products/fertilizer

- use

- and

- price.aspx#.Up40LqVXaa4.

24 USDA	National	Agricultural	Statistics	Service	data,	accessible	at http://www.nass.usda.gov/Data_and_Statistics/Pre

Defined_Queries/2010_Corn_Upland_Cotton_Fall_Potatoes/index.asp

. 25 Dow’s	corn	is	engineered	to produce an	aryloxyalkanoate dioxygenase

- 1	enzyme	(AAD

- 1)	that	confers high

- level	resistance	to	both	phenoxy	auxin	herbicides	like	2,4

- D	as	well	as	the	aryloxyphenoxyproprionate26 corn	resistant	to the	herbicides dicamba ,	glufosinate and glyphosate,	as	well	as	“FOPS

Tolerant	corn”	that	would	also	be	resistant	to	glyphosate. 26 “Fop s ” herbicides	like quizalofop	are	often	used	to	kill	volunteer	corn	in	soybeans;	that	option	would	be eliminated	with	the s e new	multi

- herbicide

- resistant	crops .		Big	Biotech	firms	frequently

cross

- license	their	traits,	which	could	easily	lead	to	corn,	and hence volunteer	corn,	with resistance	to	four	or	more	different	classes	of	herbicide. For	example, USDA	recently deregula ted	a	DuPont

- Pioneer	GE	corn	with	dual	resistanc e	to	glyphosate	and	glufosinate. DuPont

- Pioneer suggested	it	might	be combined	with	Dow’s 2,4

- D	and	”fop s ” resistance	for quad

- resistant	corn (DuPont

- Pioneer	2012,	pp.	78

- 79) .		A	patent	awarded	to	DuPont

env isions	corn	and	other	crops	resistant	to	seven	or	more	different	classes	of	herbicide (DuPont

- Pioneer	2009,	par.	33)

. Volunteer	corn	control	options	diminish as	the number	of	herbicide

- resistance	traits rises. Corn	volunteers	with	multiple	resistance	to glyphosate,	glufosinate, dicamba, “fops”	and/or other	herbicides	would	be	more	likely	to	survive,	and	if	stacked	with	rootworm	Bt,	select for CRW resistance	to	the	Bt	toxin. While	Krupke’s	work	involved	Bt	corn	expressing Monsanto’s	Cry3Bb1 ,	it	is	quite	p ossible volunteers	of	other	HR/Bt	corn	types	would express	similarly	low	levels	of	rootworm	toxin	and	also	foster	resistance.



## III. Conclusion

EPA	is	rightly	proud	of	the	mandatory	insect	resistance	management	plans	it	established for	cultivation	of	Bt crops	targeting	lepidopteran	pests.		The	Agency heeded	the	warnings and	recommendations	of	independent	entomologists,	and	prevailed	over	considerable opposition	from	industry.		IRM	for	Bt	crops	represented	the	first	time,	to	our	knowledge, that	EPA	imposed constraints	on	the	use	of	a	cl a ss	of less	harmful pesticid es to	preserve their	efficacy	and	so	forestall	the	use	of	more	toxic	pesticides that	would	ensue	in	the	event that	resistance to	the	former emerges. Because	IRM	for	this	class	of	Bt crops	has	been scientifically	sound,	it	has	succeeded	in	largely	forestalling	any	significant	resistance	in above

- ground	pests.

In	contrast, EPA’s	IRM	for	rootworm	Bt	has	been thoroughly ineffective. CFS sees several reasons	for	EPA’s	failure.

The	IRM concepts	and	modeling that	EPA	and	entomologists	developed	for	lepidopteran	Bt are	in	many	respects	inapplicable	to	rootworm	Bt,	yet	EPA	appears	unwilling	to	fully	accept the	implications. Lepidopteran	Bt	corn	deliver s a	high	dose	to	kill over	99.99% of	p ests that	exhibit	recessive,	high

- level	resistance	to	Bt	toxins.		Corn	rootworm	Bt	delivers	a	low dose	to	kill	a	relatively	low	percentage	of	pests	that	exhibit	non

- recessive,	lower

- level

(“fops”)	class	of	ACCase	inhibitor	herbicides,	such	as	quizalofop	and	cyhaolfop.		For	more	on	this	crop,	s ee	CFS comments	to	EPA	at http://www.centerforfoodsafety.org/files/cfs

- 24

- d

- comments

- to

- epa

- final

- 6

- 22

- 12.pdf

. Dow’s	corn	is	pending	deregulation	(approval for	commercial	cultivation)	by	USDA.		See	petition	09

- 233

- 01p at	http://www.aphis.usda.gov/biotechnology/petitions_table_pending.shtml

26 See http://www.monsanto.com/products/Pages/c orn

- pipeline.aspx ,	last	visited	12/3/13.27 resistance	to	Bt	toxins. While	the	difference	between	resistance	an d	susceptibility	to	Bt toxins	is	a	“bright	line”	in	European	corn	borer, the	distinction	is	muddier	for	CRW. Industry	has	ex ploited	the	less clear

- cut nature	of	Bt	resistance	in	CRW	to deny the	obvious fact	that	it	has	developed (Philpott	2011)

, and	so	avo id	serious	remedial	actions	that might involve reduced	sales	of	its	products.

EPA	must	adopt	a	more expansive	definition	of	resistance	that	aims	foremost	at	reducing the current	high rate	of	false	nega tive	resistance	assessments that are in	large	part

res ponsible	for	emerging	resistance.		The	definition	must include	“partially	resistant”	CRW. We	remind	EPA	that	with	its	current	IRM	plans,	it	has	failed	to	stem	resistance ; and so failed	to fulfill its	statutory	mandate	of	preventing	the	unreasonable	advers e	effects	on	the environment	that	are	caused	by sharply increased	use	of	organophosphate	insecticides	to kill	Bt

- resistant	CRW.

EPA’s	failure	is	due	in	large	part	to	undue	reliance	on	industry. In	contrast	to	its formulation	of	IRM	plans	for	lepidopteran Bt	corn, EPA	has consistently	privileged	industry
assessments and	views over	independent	science	in	developing	IRM	for	corn	rootworm.		As noted	above, on	at	least	two	occasions EPA	has	explicitly	rejected	the	recommendations	of Scientific	Advisory	Panels (SAP	2002,	SAP	2009) and	instead	allowed	itself	to	be	led	by faulty	industry	assessments	biased	by	self	interest (in setting	deficient refuge requirements)

. EPA	has	also flaccidly accepted	industry’s	“blame

- the

- farmer”	excuses	for resistance. EPA	made	a major	regulatory	blunder	(20%	refuge	for Cry3Bb1	corn ) based	in part	on industry

- inspired speculation	that	farmers	wouldn’t	comply	with	a	50%	refuge,	and like	industry	has	often	used	putative farmer “non

- compliance”	as	an	excuse	for	rejecting scientific	IR M	in	favor	of	expedient	but	ineffective	IRM	plans.

EPA	must	fully	comprehend	that seed	firms	have	not	been good

- faith	partner s in	IRM efforts ,	and	act	accordingly .		Since	effective	IRM	must	involve	reducing	selection	pressure, which	entails	reduced	produc t	deployment,	sales	and	hence	profits,	industry’s financial self

- interest	is	directly	opposed	to	IRM. This	self

- interest	skews	industry	science,	making	it unreliable	as	the	basis	for	regulatory	decision

- making. This	is	demonstrated	by	the	bottom line	mea sure	of	rapidly	emerging	resistance	that	has	occurred	with	use	of	industry

fashioned	IRM	plans.		One	may	also	refer	to the	lengthy	critique	of	Lefko et	al (2008)

– a study	by	DuPont

- Pioneer	scientists	that	formed	the	basis	of	DuPont’s	request	for,	and	EPA’ s grant	of,	reduced	refuge	requirements	for	an	RIB	version	of	Cry34/35Ab1	corn

– by independent	scientists in	SAP	(2009). Neither	have	seed	firms	proven	reliable	in	terms	of IRM	practice,	as	evidenced	by	the	many	deficiencies	in	Monsanto’	resistance	monit oring (BPPD	2011). EPA	should return	to	its	former	course	of	accepting	and	following	the recommendations	of	its	independent	experts.

Bt	corn	developers	have	consistently	opposed	and	weakened	resistance prevention efforts, but	have understandably proven	m uch	more	willing	to	engage	in	profitable	forms	of resistance management

. For	instance, Monsanto	prevailed	upon	EPA	to	set	a	thoroughly inadequate	20%	refuge	for	MON863,	substantially	accelerating evolution	of Cry3Bb1 resistance	in	CRW.		Now	that	resistanc e	has	emerged,	Monsanto	is	eager ly exploit ing it	as

an opportunity	to market SmartStax corn ,	particularly	as	a	tool to facilitat e the	resistance

-2 8 promoting and	generally	detrimental agronomic	practice	of	corn

- on

- corn ;	continuous SmartStax	corn,	however,	wil l	accelerate the	evolution	of additional	resistance	(to Cry34/35Ab1)

. While eager	to promot e these	profitable	forms	of short

- term resistance management,	industry	makes less	profitable	but more	effective	tactics	(e.g. periodic	use	of

non

- Bt	corn)	much	mor e	difficult	for	farmers	to	implement	by	slashing	their	offerings	of high

- quality conventional	corn	seed.		Resistance prevention must	take	center	stage	as	EPA moves	to	reform	IRM.

None	of	this	is	inevitable.		While	biotech

- seed	firms (like	most	others) wil l	normally act	to maximize	their	financial	self

- inter est,	it	is	not	inconceivable	that	they	might	pursue	more responsible	paths	that	sacrifice	some	profit if	prodded	by	proactive	regulators. In	this context, seed	firms sh ould	implement	a	mandatory	resista nce	management	plan	for	all	low

dose	rootworm

- active	Bt corn	events (which	includes	today’s	pyramids) as	part	of	the technology	use	agreement	that	farmers	sign	upon	seed	purchase.		The	IRM	plan	would require	that farmers grow	the	Bt	corn	in	rotation	with	a nother	crop	(e.g.	soybeans) or	with

non

- Bt	corn.		The	Bt	corn	would	have	to	be	rotated	every	other	year,	or	perhaps (to	permit greater	flexibility) planted no	more	than	two	years	of	every	four. Seed	f irms	should	also drop	their	efforts	to zero	out refuge requirements,	and	scale	up	production	of	high

- quality conventional	seeds.

There	is	precedent	for such	an approach.		As	part	of	its	stewardship	program	for	its herbicide

- resistant,	Clearfield	wheat,	BASF	requires	that	growers	abstain	from	growing	it, and	f rom	applying	the	associated	herbicides	(imidazolinones),	more	than	two	of	every	four years	(OSU	2010).		The	goal	is	to	deter	the	emergence	of	resistant	weeds	and	so	prolong the	effective	life	of	the	herbicide

- resistance	trait	through	restraints	on	its	use 27

– precisely analogous	to the	purpose	of	IRM	for	Bt	crops.

There	is	also	precedent	for	a	proactive	regulatory	stance	by EPA.		One	model	is	the comprehensive	IRM	program	for	Bt	cotton	that	was successfully implemented	by Australian	regulators	in	collaborat ion	with	industry.		With	more	respect	for	science and law, and	the	requisite	political	will,	EPA	could	even	now	redress	the	huge	deficiencies	in	its IRM	program. If	decisive	action	is	not	taken	soon, however, EPA	and	industry	will	have squandered	the	valu able	resource	of	rootworm

- active	Bt	toxins.

27 This	example	should	not	be	misconstrued	as CFS endorsement	of	Clearfield	wheat,	only	the	concept	of reducing	selection	pressure	for	resistance	through	restraints	on	use.		CFS	opposes	herbicide

- resistant	crops (how ever	they	are	developed,	via	genetic	engineering,	mutagenesis	or	conventional	breeding)	because	they foster	greater	use	of	and	dependence	on	often	harmful	pesticides ,	and	increase	selection	pressure	for resistant	weeds .		In	the	case	of	Clearfield	wheat, on e	clear	harm	of	the associated	class	of	herbicides (imidazolinones) is	that	they increase	the	risk	of	bladder	and	_____	cancer in	farmers	exposed	to	them.29 

## IV

. Recommendations

1) Establish	a	simple,	single

- criterion	definition	of	resistance	along	the	lines discussed	above (comments	on	Question	4) that	reduces	as	much	as	possible the potential	for false	negative resistance	assessments

2) Increase	refuge	requirements	for	all	rootworm

- active	Bt	corn	events	as

recommen ded	by	Tabashnik	&	Gould	(2012)

– 50% for	single

- tox in	Bt	corn	and 20%	for	pyramids

– with	phase

- in	as	needed	allow	for	seed	firms	to	multiply sufficient quantities	of needed	seeds

3) Mandatory	IRM	involving	rotation away from	rootworm	Bt	corn

4) EPA	should	increase	the	role	of	independent	scientists	and	reduce	that	of	seed firms	in	every	aspect	of	IRM

– for	instance, resistance	monitoring ,	diagnostic
assays, definition	of	resistance,	and	setting	of	refuge	size	requirements

– in	light of seed	firms’ failure	to	successfully	detect	a nd	notify	EPA	of	the	emergence	of resistant CRW.

5) EPA	should	make	publically	available	the	resistance	monitoring	data	reported	to it by	industry,	and/or	provide	complete and	standardized descriptions	of	it	in relevant	documents	released	to	the	public ,	in	particular	the	number	of unexpected	damage/resistance	reports	broken	down	by	state	and	county

.



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SAP (1998).		Final	report	of	the	FIFRA	Scientific	Advisory	Panel	Subpanel	on	Bacillus thuringiensis	(Bt)	plant

- pesticides	and	resistance	management,	Environme ntal	Protection Agency,	1998. http://www.epa.gov/scipoly/sap/meetings/1998/0298

_ mtg.htm

. SAP	(2002). Final	report	of	the FIFRA	Scientific	Advisory	Panel	on Corn	Rootworm Plant

Incorporated	Protectant	Non

- Target	Insects	and	Insect	Resistance	Management	I ssues , Environmental	Protection	Agency,	2002

. http://www.epa.gov/scipoly/sap/meetin gs/2002/august/august2002final.pdf

. SAP	(2009).		Final	report	of	the	FIFRA	Scientific	Advisory	Panel	on Evaluation of	the Resistance	Risks	from	Using	a	Seed	Mix	Refuge	with	Pioneer’s	Optimum	AcreMax	1	Corn Rootworm

- Protected	Corn,”	Environmental	Protection Agency,	2009. http://www.epa.gov/scipoly/sap/meetings/2009/february/232009finalreport.pdf

Smith,	P	&	Garnett	E	(2013).		“Rotation	resistant	rootworm:	corn	grower s	should	revisit rootworm	tactics	for	2014,”	DTN	Progressive	Farmer,	9/3/13. http://www.dtnprogress ivefarmer.com/dtnag/common/link.do?symbolicName=/free/ne33 ws/template1&product=/ag/news/bestofdtnpf&vendorReference=cdc37f49

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, Stewart,	J.	(2011).	Volunteer	Corn	Reduces	Yield	in	Corn and	Soybean	Crops.	University News	Service,	,	March	17,	2011

. http://www.purdue.edu/newsroom/general/2011/110317JohnsonCorn.html

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- Pioneer’s	petition	for determination	of	Nonregulated	status	for	insect

- resistant	and	herbicide

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- 004114

- 3,”	USDA	Animal	and	Plant	Health	Inspection	Service,	February 2013. http://www.aphis.usda.gov/brs/aphisdocs/11_24401p_dea.pdf .		See	also	CFS
comments on	this	draft	environmental	assessment,	at: http://www.centerforfoodsafety.org/files/cfs

- comments

- dupont

- pioneer

- 4114

- maize

-- final_43107.pdf

.