NCC Comments On EPA’s Proposed “Guidance for Herbicide Resistance Management, Labeling, Education, Training, and Stewardship

The NCC submitted Comments on EPA’s Proposed “Guidance for Herbicide Resistance Management, Labeling, Education, Training, and Stewardship.

Published: September 2, 2016
Updated: September 2, 2016

September 1, 2016

Office of Pesticide Programs
Regulatory Public Docket (7502P)
U.S. Environmental Protection Agency
1200 Pennsylvania Ave., NW Washington, DC 20460

RE:  Docket No. EPA-HQ-OPP-2016-0226

The National Cotton Council (NCC) appreciates the opportunity to provide comments regarding the Environmental Protection Agency’s (EPA’s) “Guidance for Pesticide Registrants on Pesticide Resistance Management Labeling and Guidance for Herbicide Resistance Management Labeling, Education, Training, and Stewardship.”  The NCC recognizes the impact of pest populations evolving resistance to pest management products and has actively engaged in promoting awareness and educational materials to NCC membership.  However, the NCC does not agree with EPA’s assertion of regulatory authority and urges EPA to recognize the distinction between individual and population resistance.  Similarly, NCC urges EPA to recognize scientific/academic principles are not absolute and do not easily transfer to regulatory and legal obligations.  Although the NCC does not agree with EPA’s claim of authority regarding resistance management, the NCC has identified issues of additional concern within the draft document that warrant clarification if EPA should decide to expand its role.

The NCC is the central organization of the United States cotton industry.  Its members include producers, ginners, cottonseed processors and merchandizers, merchants, cooperatives, warehousers and textile manufacturers.  A majority of the industry is concentrated in 17 cotton-producing states stretching from Virginia to California. The NCC represents producers who cultivate between 10 and 14 million acres of cotton.  Annual cotton production, averaging approximately 16 to 20 million 480-lb bales, is valued at more than $5 billion at the farm gate.  The downstream manufacturers of cotton apparel and home furnishings are located in virtually every state. Farms and businesses directly involved in the production, distribution and processing of cotton employ more than 230,000 workers and produce direct business revenue of more than $27 billion.  Accounting for the ripple effect of cotton through the broader economy, direct and indirect employment surpasses 420,000 workers with economic activity well in excess of $120 billion. In addition to the cotton fiber, cottonseed products are used for livestock feed, and cottonseed oil is used as an ingredient in food products as well as being a premium cooking oil.


The NCC appreciates EPA’s desire to “preserve the useful life of pesticides” while acknowledging activities are aimed at “combating and slowing the development of pesticide resistance.”  Resistance is often discussed among scientists with an unspoken understanding that the conversation is referring to population frequencies rather than individual genetics.  The NCC urges EPA to clarify the distinction for the benefit of the general public, and to clarify that it is assumed some individuals exhibit resistance prior to the introduction of the pesticide products.  Subsequently, the over reliance on single Modes of Action (MOA) alters populations through selection pressure from the pesticide resulting in “survival of the fittest individuals” (i.e., resistant individuals) with the number of resistant individuals increasing in the overall population.  This principle is often misrepresented or misunderstood and is the cornerstone of resistance management.  First, it clarifies the assumption that resistance is present at some level in the population.  Second, it clarifies that the selection pressure is the over reliance on the MOA.  Third, it provides understanding that the desire is to delay the rate of increase for resistant individuals in the population, thereby extending the useful life of the pesticide.  Clarification and emphasis of these points set the foundation for identifying activities attempting to delay the resistance rate of increase in the population (i.e. delaying population resistance).


The NCC would request correction on page 3, lines 2 and 3 which currently states “There are 80 unique weed species with herbicide resistance in the U.S.”  The statement implies the 80 weed species are resistant to all herbicides, and the NCC does not believe that was the intended meaning from EPA.  Additionally, a correction to line 4 should insert “one” prior to “MOA.”

On page 4, paragraph 2, the first sentence is misleading and believed to be an error.  The NCC encourages restating the sentence to reflect selection pressure placed on the population from the repeated use of a single mode of action.  The NCC encourages EPA to clearly distinguish whether comments are referring to individual genetics or genetic frequencies in the population.  For example, page 4, line 6, states “The speed at which this genetic shift occurs depends on the intensity of the selection pressure.”  The use of “genetic shift” does not adequately convey the meaning “genetic frequency in the population” or “resistant frequency in the population.”  Additionally, the next sentence (line 7) is unclear and should have the word “from” removed.

The NCC respectfully disagrees with Table 1, Agronomic and Management Practices, bullets referring to trait.  The NCC believes the intent is to identify whether or not the management practice has heavy reliance on a single mode of action which is more likely if the farm is planted to crops with a herbicide resistant (HR) trait.  However, the trait does not mandate the use of the single mode of action.  For example, glyphosate resistant cotton can be grown using conventional cotton herbicides.  The statement should be rephrased to emphasize the chemistry imposing the selection pressure rather than implying traits somehow impose selection pressure.  The negative connotation placed on traits is misleading to the public.


The NCC believes EPA should clarify the difference between “naturally occurring resistance” and “naturally tolerant”.  The definitions for herbicide resistance and herbicide tolerance seem to be the same, but also appear to indicate difference based on initial population response (“ability of a plant” vs. “ability of a species”).  If this is the case, at what population frequency is the population naturally tolerant?  Similarly, the NCC finds the following sentences confusing:

“Herbicide resistance – The inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type.  Resistance may be naturally occurring …”.  If resistance is naturally occurring, is it not a wild type?  Again, the NCC believes the intent is to distinguish between individual plants with low frequency in the overall population.

Page 6 defines “Likely herbicide resistance” to be synonymous to “possible herbicide resistance”.  The NCC urges EPA to use possible herbicide resistance rather than implying it is likely.  The use of likely confuses communication with producers when the follow-up fails to prove the resistance.  Additionally, the bullet “Failure to control a weed species normally controlled by the herbicide at the dose applied, especially if control is achieved on adjacent weeds;” raises a question of what level of control failure?  The sentence uses “weed species” suggesting the reference is to a population effect, but does not identify what level indicates likely herbicide resistance.

Regulatory Basis for Herbicide-Resistance Management

Basis and Reporting of Likely Resistance

The NCC has a clear understanding of the importance of resistance management and continues to promote educational materials and programs that encourage resistance management practices.  The NCC does not agree that the development of resistance qualifies under FIFRA 2(bb) “unreasonable adverse effect on the environment.”  As previously stated, resistance can be naturally occurring.  The naturally occurring resistance may or may not be the dominant frequency of the population.  If it is the dominant frequency, the herbicide provides little control for that species, but may still have value due to the many other weed species that continue to be controlled.  The balance between risk and benefits of a herbicide must be weighed on a case-by-case basis, not generalized with claims that one resistant weed species alters the balance.  There are many herbicide products that do not control all species when used alone.  However, in combination with another herbicide the two may efficiently provide necessary weed control.

The NCC believes resistance is a biological evolutionary process that does not meet the intent of FIFRA’s “adverse effect.”  Resistance is a natural biological response or adaptation to a change in the environment that favors survival of certain genetic types.  Resistance does not qualify as an “unreasonable risk to man or the environment nor a human dietary risk from residues.”

Reporting under 6(a)(2)

EPA cites section 6(a)(2) of FIFRA requiring “if at any time after the registration of the pesticide the registrant has additional factual information regarding unreasonable adverse effects on the environment of the pesticide, the registrant shall submit such information to [EPA].”  The NCC again does not agree with the interpretation that a resistant species automatically triggers an adverse effect.  Without a risk-benefit analysis, it cannot be concluded that the benefit has changed based on resistance of an individual species.  EPA’s intent to require reporting of “Likely herbicide resistance” is of additional concern given the current position that “Likely herbicide resistance” is synonymous to “possible resistance”.  It would appear that EPA is requiring reporting of any weed surviving in any field.  This will impose an overly burdensome task for registrants and stakeholders.


EPA states the position that “One of FIFRA’s requirements for labeling is that it not be false or misleading in any particular.”  Based on that requirement, EPA asserts the development of resistance “could cause the pesticide’s outdated label to be misleading making the product misbranded and unlawful for sale or distribution. Flaws or inadequacies in the labeling could lead EPA to cancel the product under FIFRA § 6(b).”

The NCC respectfully points out there are multiple weed species in a given production field.  Based on scouting, management determines the most appropriate and economical herbicide or herbicide combination to use.  The NCC would urge EPA to recognize a product often controls multiple other species even if one species develops resistance to the herbicide.  Thus, producers need access to multiple MOAs, not fewer.  The NCC urges EPA to not begin cancelling products on grounds related to a resistant weed species.  The NCC would urge EPA to work with registrants to allow distribution of labeled stock and if necessary amend labels for new stock.

Stakeholder Input

The NCC agrees with EPA’s statement “Management of herbicide-resistant weeds, both in mitigating established herbicide-resistant weeds, and in slowing or preventing the development of new herbicide-resistant weeds is a complex problem without a simple solution.”  The NCC agrees that coordinated efforts with growers, agricultural extension, academic researchers, scientific societies, pesticide registrants, and state and federal agencies are necessary to address this problem.  The NCC believes this is best accomplished through educational programs with consistent, reliable messages with consideration given to geographical and climatic differences.  However, the NCC would urge EPA to not focus solely on “under ideal conditions,” but to challenge the participants with real-world conditions beyond the control of producers.  For instance, what if weather events, after planting, delayed weed control until weeds were taller than desired?  How would a late cold front impact weed control activities?  At what point is there no acceptable “rescue treatment” for fields with high weed pressure due to unforeseen circumstances?

The NCC appreciates that EPA has presented to the Weed Science Society of America (WSSA) this herbicide-resistance management strategy, but does not agree that EPA should consider that meeting of a professional society with mostly academic members to qualify as stakeholder input.  The NCC believes producer input and management decision processes are critical for meaningful herbicide resistance management strategies and must include producers.  Implementation at the field level is critical, and the resistance management strategies should involve input and understanding of implementation challenges from producers.


NCC appreciates EPA Office of Pesticide Programs (OPPs) desire “to provide growers and users with detailed information and recommendations to slow the development and spread of herbicide resistant weeds.”  The NCC has collaborated with agricultural extension specialists and researchers to develop educational DVDs with the same goal.  However, the NCC does not endorse EPA’s proposed three risk categories for herbicide chemistries (low concern of resistance development, moderate concern of resistance development, and high concern of resistance development).  The NCC believes EPA has not presented a sound scientific basis for this categorization which is implied in EPA’s statement that a product may move to a higher risk concern if resistant weeds are discovered.  It would seem apparent that such a change would also “trigger” EPA’s labeling regulation thus requiring all products to be re-labeled prior to distribution and use.  The cost could be extreme and should not be implemented based on a concept that has not been scientifically demonstrated.  For example, the introduction of glyphosate herbicide was praised by many academic and extension scientists who argued weeds would not develop resistance to the product, and that growers could achieve control and save money by reducing the use rate.  This example demonstrates that scientists had a low concern for resistance development, but the concern began to shift when field failures were confirmed.

The NCC additionally urges EPA to refrain from linking “herbicide resistant crops” to herbicide resistant weeds.  As previously stated, it is the over-reliance of a MOA that places the selection pressure on the weed population.  Herbicide resistant crops do not influence the weed population or the weed’s resistance capability.  Maintaining the emphasis on over-reliance of a single MOA shortens the message and maintains the relevant science.

The NCC believes elements 1 through 4 are appropriate useful information for management decisions.  The MOA grouping as well as seasonal and annual maximum application rates (elements 1 and 2) are extremely valuable pieces of information in order to make informed resistance management decisions.  Best Management Practices and scouting information should be provided as educational messages. 

Elements 5 through 8 are being proposed for inclusion on moderate and high risk category herbicides.  The definition of “likely herbicide resistant” has previously been addressed and is objectionable.  A label statement that growers should report lack of performance to registrants or their representatives is not objectionable and is a common practice when growers do not believe the product they purchased performed as expected.  Element 7 proposes a separate label table of confirmed resistant weed species with the effective or recommended rates specifically for these weeds.  This element seems to pose a conflict with EPA’s “labeling” interpretation and the development of scientific “effective or recommended rates” should a resistant weed species arise.  The conflict is likely to be increased due to the geographic area of early detection prior to spread through the production regions.  When would EPA require registrants to revise the label? Would the requirement to re-label be based on the first identified resistance case in a remote location or when it is first identified in a state, a county, a region, or all regions?  Element 8 proposes to require registrants to report yearly to EPA and users likely and confirmed resistance.  Recognizing the proposed definition of likely means the same as possible resistance, the reporting requirement would undoubtedly contain a vast amount of reports that were not actual resistance and the vast amount of information would not highlight the important resistant cases.

Elements 9, 10, and 11 are proposed requirements for herbicides categorized as high concern for resistance development.  Element 9 proposes to recommend educational and training material for users that may include resistance management plans, remedial-action plans, and other education and training materials on herbicide resistance and its management.  EPA also proposes to recommend registrants work with “agricultural extension, crop consultants, individual crop associations, the Herbicide Resistance Action Committee, and the U. S Department of Agriculture in developing these plans.”  The NCC appreciates the EPA’s desire to be all inclusive, but urges caution be exercised in order to timely produce educational material without impairing local flexibility based on local agricultural extension/research expertise.  Element 10 proposes to require formulated products with more than one MOA contain separate lists for each MOA to specify weeds controlled and their minimum recommended rate.  Element 11 proposes “additional case-specific requirements” stating “EPA and registrants may identify additional measures that are deemed appropriate…” which is followed with an example of mandatory crop rotation or time-limited registration, among other elements.  The NCC finds this open-ended element in a guidance document to suggest a lack of transparency and to create uncertainty in the agricultural production decision making process, including resistance management planning.  Creating uncertainty of future availability invites “use while available” mentality that could lead to over-reliance on a product.  The NCC urges EPA to avoid open-ended elements such as element 11 in a guidance document.

Closing Comments

The NCC urges EPA to recognize resistance management plans are as diverse as the number of weed species across production areas, and similarly any development or a remedial action plan would depend on which weed species are located in which area of the U.S.  The NCC believes EPA’s statement on page 13, paragraph 3 that “developing resistance management plans/remedial action plans are largely one-time activities for each herbicide” is incorrect because of the extreme diversity of weeds that may be controlled by a product.   The NCC agrees that certain academic principles/goals/Best Management Practices apply to all cases at a large scale, but do not contain the details that must be developed at the field level.  The NCC urges EPA to continue educational efforts and urges EPA to support local and state agricultural extension and research experts as they provide local and state stakeholders respective recommendations based on local and state research.  As such, providing appropriate plans on labels is not practical. 

While the principles are supported by the NCC, the NCC urges EPA to recognize the Best Management Practices for Herbicide-Resistant Weeds (Appendix III) are best case circumstances, but are seldom possible as a legal obligation for real world production.  For example, planting to a weed free field is desired, but additional weed germination is possible between pre-plant burndown and planting.  To not allow weed-escapes to produce seeds, roots or tubers is a general goal, but if the weed does escape (i.e. survives after the application) it has already produced roots and could be claimed as evidence of non-compliance.  Prevention of field-to-field and within-field movement of weed seed or vegetative propagules is not possible if the seed is moved by means not controlled by the grower (e.g. birds, wind, rain, etc.).  These principles are valuable, over-arching recommendations, but do not translate into achievable label mandates.

The NCC appreciates the opportunity to provide these comments to EPA’s proposed “Guidance for Herbicide Resistance Management, Labeling, Education, Training, and Stewardship. The NCC recognizes the critical importance of preserving the utility of current herbicide MOAs, and recognizes the lack of development of new MOAs. Placing additional costs and burdens on the agricultural sector will not enhance the research and development of new MOAs.  The NCC agrees with EPA’s statement of the complexity of herbicide resistance management and urges EPA to focus on clear, concise educational messages that bring the focus to the root of the issue – think survival of the fittest and avoid over-reliance on a single MOA.




Reece Langley
VP – Washington Operations