USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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USEPA. 2016. Recommended Revisions to Chapter 11.VI.G of EPA’s Office of Pesticide

Programs’ Label Review Manual. 

As part of EPA’s updates to the Pesticide Registration Notice 2016-X, “Guidance for Pesticide

Registrants on Pesticide Resistance Management Labeling,” EPA is also recommending the 

following revisions to Chapter 11.VI.G of the Office of Pesticide Program’s Label Review

Manual (LRM). 

G. Resistance Management Labeling Considerations

The Office of Pesticide Programs (OPP) of the EPA has developed voluntary pesticide

resistance management labeling guidelines based on target mode of action (MOA) for

agricultural uses of pesticides (Pesticide Registration Notice 2016-X). MOA refers to the

biochemical mechanism by which the pesticide acts to control the pest and should not be

interpreted to imply that these chemicals share a common toxicological mechanism for

purposes of cumulative human health risk assessment under FIFRA and the Federal Food,

Drug, and Cosmetics Act (FFDCA).

Rotation of MOA action was selected as a primary pest/pesticide resistance management

strategy for this voluntary regulatory initiative, because it is the easiest method for reducing

the likelihood of resistance, especially monogenic resistance, and it will help reduce the

likelihood of resistance caused by other mechanisms. The rotation of MOA is a 

scientifically-sound, flexible, and practical resistance management strategy. Other

management practices that will reduce resistance include application timing, crop rotation

and other cultural practices, and application equipment cleaning. The voluntary resistance

management guidelines based on rotation of MOA are found in Pesticide Registration

Notice 2016-X (supersedes PR Notice 2001-5). These guidelines were developed under the

auspices of the North American Free Trade Agreement (NAFTA) by both the U.S. and

Canada. Canada published similar guidelines to those of the U.S. in October 1999 as

Regulatory Directive 99-06 and subsequently updated these guidelines in December 2013 as

Regulatory Directive 2013-04. Both countries agreed that uniform labeling guidance across

North America would encourage adoption of resistance management strategies and help

reduce the development of pest resistance. In support of these goals, the resistance

management guidelines based on rotation of MOA provide guidance to users about pesticide

classes and pesticide management strategies. Adoption of these guidelines will provide

users with easy access to information regarding target site/mode of action resistance.
USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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The objective of the voluntary resistance management labeling guidelines (PR Notice 2016-

X) is to include pesticide mode of action symbols and resistance management

recommendations on the labels of all new and existing pesticide products for agricultural

uses. The management of pesticide resistance is an important part of sustainable pest

management and this, in conjunction with alternative pest management strategies and

Integrated Pest Management (IPM) programs, can make a significant contribution to

reducing pesticide risk to humans and the environment. 

Mode of Action Information Box

To ensure consistency in pesticide grouping and labeling, and to contribute to the

management of pesticide resistance, the following labeling guidelines have been developed

for agricultural uses of pesticides. The classification schemes shown in this section are based

on the mode of action. Herbicides, fungicides/bactericides, and insecticides/acaricides are

separately grouped according to their primary modes of action by various Resistance Action

Committees. Typically, these committees consist of representatives of the pesticide industry,

researchers, extension specialists and regulatory officials. The pesticide groupings are

provided by the Weed Science Society of America (WSSA; http://www.wssa.net, the 

Herbicide Resistance Action Committee (HRAC; http://www.hracglobal.com), the Fungicide

Resistance Action Committee (FRAC; http://www.frac.info) and the Insecticide Resistance

Action Committee (IRAC; http://www.irac-online.org). The mode of action groups plus the

identifier numbers and/or letters (i.e., symbols or codes) for herbicides,

fungicides/bactericides and insecticides/acaricides may be accessed through the websites of

the different Resistance Action Committees (listed in the following paragraphs). If a product

contains an active ingredient that currently does not have a known mode of action, registrants

should consult the pesticide groupings provided by the appropriate Resistance Action

Committees, as there is a generic classification number or letter provided for these pesticides

as well.

WSSA uses numbers 1 through 30 to identify the MOA groups for herbicides. The number 26

is used for compounds with a non-classified MOA. For herbicides, EPA recommends that the

WSSA MOA identifier codes be used to ensure consistency with existing herbicide labels that

follow this scheme. HRAC uses alphabetical letters instead of numbers for the MOA groups

for herbicides. The HRAC website contains a cross reference between the HRAC and the

WSSA MOA identifier codes, so the WSSA MOA codes can be found at the following

HRAC website: http://www.hracglobal.com/pages/classificationofherbicidesiteofaction.aspx. 
USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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For fungicides, FRAC uses different letters (A to I, with added numbers) to distinguish

fungicide groups according to their biochemical MOA in the biosynthetic pathways of plant

pathogens. EPA recommends that the FRAC MOA identifier codes be used for developing

fungicide mode of action grouping information on labels for pesticides containing fungicides.

The FRAC code list can be found at: http://www.frac.info, where the reader is advised to use

the search term “code list” in the site’s search function to locate the most current groupings.

For insecticides, IRAC uses a combination of numbers and letters to identify various MOA

groups. EPA recommends that the IRAC MOA identifier codes be used for developing

insecticide mode of action grouping information on labels for pesticide containing

insecticides. The IRAC MOA list and identifier codes can be found at: 

http://www.irac-online.org/modes-of-action. 

The recommended mode of action code should be provided on the end-use product label in a 

mode of action information box following the standard format outlined below:

Location: Upper right corner of front panel of label

Content: 

• Include the name of the ACTIVE INGREDIENT in the first column

• Include the word “GROUP” in the second column

• Include the MODE OF ACTION CODE in the third column

• Include the type of pesticide (i.e., HERBICIDE or FUNGICIDE or

INSECTICIDE) in the fourth column; 

Appearance: All text should be in black, bold face and all caps on a white background,

except the mode of action code, which should be white, bold face and all caps on a 

black background; all text and columns should be surrounded by a black rectangle.

Mode of Action Information Box Examples

1. General example

The format of the mode of action information box that the Agency suggests for agricultural

pesticide labels is provided in Figure 1 below. 
USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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Figure 1. Recommended pesticide mode of action information box format.

NAME of

ACTIVE

INGREDIENT

GROUP

MODE OF ACTION CODE 

as Designated by WSSA, FRAC, or

IRAC

Type of Pesticide, e.g. 

“HERBICIDE”, “INSECTICIDE”,

“FUNGICIDE”, etc

2. Single active ingredient with a single mode of action code

The mode of action information box appropriate for an agricultural pesticide with a single

active ingredient, the insecticide aldicarb, is provided as an example below in Figure 2. 

Figure 2. Example of a pesticide mode of action information box for a pesticide

containing a single active ingredient with single mode of action code.

ALDICARB GROUP 1A INSECTICIDE

3. Pesticide with multiple active ingredients

The mode of action information box appropriate for an agricultural pesticide with multiple

active ingredients is provided in Figure 3 below; a pesticide containing tebuconazole serves

as an example of an active ingredient with MOA group designations as both an insecticide

and a fungicide. For products containing an active ingredient that has multiple mode of action

groups, all applicable designations, as described by the Resistance Action Committees

(RACs) should be used.

Figure 3. Example of a pesticide mode of action information box for a pesticide containing two

active ingredients with mode of action codes for two pesticide types.

TEBUCONAZOLE GROUP 3 FUNGICIDE

LAMBDA-CYHALOTHRIN GROUP 3A INSECTICIDE

4. A single active ingredient with multiple mode of action group designations within a 

pesticide type

WSSA and HRAC do not have a specific code for single active ingredients that have multiple
USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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modes of action. Therefore products that contain an herbicide active ingredient that has

multiple mode of action groups should identify all applicable MOA codes, as identified by the

WSSA. Fluometuron serves as an example of an herbicide with multiple MOA group

designations. Note that FRAC and IRAC have specific designations for single active

ingredients that have multiple modes (i.e., target sites) of action. 

Figure 4. Example of a pesticide mode of action information box for an herbicide containing a 

single active ingredient with multiple mode of action codes.

FLUOMETURON GROUP 7 13 HERBICIDE

5. A single active ingredient with multiple mode of action group designations across

pesticide types 

The mode of action information box appropriate for an agricultural pesticide containing a 

single active ingredient with multiple mode of action group designations across multiple

pesticide types is provided in Figure 3 below. The pesticide tolfenpyrad serves as an example

of an active ingredient with MOA group designations as both an insecticide and a fungicide.

For products containing an active ingredient that has multiple mode of action groups, all

applicable designations, as described by the Resistance Action Committees (RACs) should be

used.

Figure 3: Example of a pesticide mode of action information box for a pesticide containing one

active ingredient with mode of action codes for two pesticide types.

TOLFENPYRAD

GROUP 21 INSECTICIDE

GROUP 39 FUNGICIDE

6. A product containing multiple active ingredients with any number of modes of action

The mode of action information box for a pesticide containing multiple active ingredients is

provided in Figure 4 below. Each active ingredient, listed by decreasing percentage in the

formulation, should have its MOA symbol displayed. An example of a product containing

herbicides quinclorac, 2,4-D, and dicamba is provided. 
USEPA Draft Revisions to Chapter 11.VI.G of OPP’s LRM - March 2016

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Figure 4: Example of a pesticide mode of action information box for a pesticide containing two

more active ingredients represented by any number of modes of action.

QUINCLORAC GROUP 4 26 HERBICIDE

2,4-D GROUP 4 HERBICIDE

DICAMBA GROUP 4 HERBICIDE

7. Product containing more than one registered pesticide packaged and sold together (ie.,

co-pack) with any number of modes of action

Pesticide products containing more than a single registered pesticide product that are

packaged in separate containers, but sold together as a single unit (i.e., co-packs), should

present the mode of action information boxes for all components on the outer packaging and

the appropriate MOA information box for an individual component on the component

container label (i.e., where each active ingredient component is in a different container, MOA

group information for each active ingredient in a component should be clearly placed on each

component container). The order in which the components are listed in the outer package

mode of action information box does not matter, but each component is to be clearly

indicated. The mode of action information box for each component should follow the

conventions established above; see Figure 6 below.

Figure 5: Example of a pesticide mode of action information box for a pesticide product

containing more than one registered pesticide packaged and sold together (i.e., co-pack) with

any number of modes of action. 

Outer Packaging Label

COMPONENT A 

TEBUCONAZOLE GROUP 3 FUNGICIDE
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COMPONENT B 

CHLOROTHALONIL GROUP M5 FUNGICIDE

Individual Component Container Label Mode of Action Information Boxes

[Container Label of Component A] 

TEBUCONAZOLE GROUP 3 FUNGICIDE

[Container Label of Component B] 

CHLOROTHALONIL GROUP M5 FUNGICIDE

Resistance Management Statements

In addition to the MOA classification symbols, a registrant may choose to have resistance

management statements on the label. If used, these statements should be included in the

“Use Directions” for end-use products for the control of weeds, plant pathogens (diseases),

insects and mites under the heading “Resistance Management Recommendations”. These

statements should be clearly distinguished from mandatory statements (see PR Notice

2000-5, “Guidance for Mandatory and Advisory Labeling Statements”) on the pesticide

label to avoid confusion to the users.

Pesticide Registration Notice 2016-X provides examples of standard resistance management

labeling statements that focus on the following areas: (1) avoid repeated or sequential use of

products in the same MOA class through rotation of MOA; (2) if tank mixes or premixes are

legally allowed, makes sure each compound is from a different MOA class; (3) use an

effective IPM program; (4) monitor for loss of product performance; (5) contact your

extension specialist, certified crop consultant, or manufacturer for the latest resistance

management information; and (6) contact the pesticide producer to report loss of efficacy.

Alternatively, registrants may supply their own resistance management labeling statements
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that address these same areas. 

Registrants may also choose to have specific mandatory statements regarding resistance

management, but these statements would not fall under “Resistance Management

Recommendations”.