What Are IRAC Groups in Insecticides?

If you frequently come across IRAC Group 3A, 4A, 5, 6 or 28 when comparing different insecticides, what exactly do these numbers and letters represent?

Put simply, IRAC Groups are a classification system used to identify the modes of action of insecticides, helping users understand how different active ingredients affect pests and providing a basis for Insecticide Resistance Management.

For example, imidacloprid and dinotefuran are two different active ingredients, but both belong to IRAC Group 4A. It would be inaccurate to assume that they offer completely independent resistance management options simply because their product names are different.

Conversely, Bifenthrin and Imidacloprid belong to Group 3A and Group 4A respectively and have different modes of action; however, this does not mean that the two can be directly interchanged for any crop, any pest or any application programme.

Therefore, understanding IRAC Groups is not merely a matter of memorising a coding table; more importantly, it involves learning to integrate this classification information with target pests, product registrations and actual pest control requirements.

For pesticide importers, distributors and brand owners, this also forms the basis for establishing a sound insecticide product portfolio. When planning products, in addition to considering the active ingredient, concentration and formulation, one should also examine the product’s IRAC Group and the role it can play within the resistance management strategy of the target market. You can learn about relevant product categories from the POMAIS Crop Protection Product Portfolio, and then evaluate a suitable product portfolio based on target crops and market demand.

What Does IRAC Stand For?

IRAC stands for the Insecticide Resistance Action Committee.

IRAC is dedicated to promoting insecticide resistance management and, through its Mode of Action Classification, assists the agricultural, crop protection and pesticide industries in identifying the modes of action of different active ingredients.

This classification system groups insecticides with related modes of action into corresponding categories, enabling users to identify relationships between active ingredients and formulate more effective control strategies.

At the time of writing, the latest version of the classification officially published by IRAC is Mode of Action Classification Version 11.5, released on 11 February 2026.

What Is a Mode of Action?

Mode of Action, abbreviated as MoA, refers to the biological process through which a pesticide affects the target pest.

Different pesticides may act on a pest’s nervous system, energy metabolism, growth and development, or other key physiological processes.

For example:

• Some insecticides work by interfering with the transmission of nerve signals in pests.

• Certain insecticides affect the growth and development or moulting process of pests.

• Certain insecticides interfere with mitochondrial energy metabolism.

• Certain insecticides act on specific receptors or ion channels.

The value of IRAC Groups lies in helping users distinguish between these modes of action.

It should be noted that IRAC is an industry-standard technical framework for classifying modes of action and managing resistance; it is not a pesticide registration authority. The fact that an active ingredient belongs to a particular IRAC Group does not mean that all products containing that ingredient are authorised for use on the same crops or against the same pests.

What Does an IRAC Group Number Mean?

IRAC Group numbers are used to identify the primary mode-of-action classification of insecticides.

Different numbers typically correspond to different biological targets or modes of action. Some main groups are further subdivided into subgroups, such as Groups 3A, 4A, 4C and 4D.

The Group Number does not represent a ranking of efficacy, toxicity level or safety rating.

It cannot be assumed that an insecticide in Group 28 is necessarily more potent than one in Group 4A, nor can the Group Number alone be used to determine whether a particular product is safer or more suitable for a specific crop.

IRAC Groups vs. Chemical Classes

IRAC Group, Chemical Class and Active Ingredient are concepts at three different levels.

For example, Imidacloprid belongs to the Neonicotinoids and is classified under IRAC Group 4A.

Different manufacturers may market Imidacloprid under different brand names, but a change in brand name does not automatically alter its classification by mode of action.

Similarly, a change in formulation from SC to SL, or a change in the concentration of the active ingredient, does not in itself constitute grounds for classifying the product into a new IRAC Group.

What Do the Letters in IRAC Subgroups Mean?

Some IRAC main groups are further subdivided into subgroups to distinguish between different chemical classes or related classifications.

For example:

• Group 3A: Pyrethroids / Pyrethrins.

• Group 4A: Neonicotinoids.

• Group 4C: Sulfoximines.

• Group 4D: Butenolides.

• Group 4E: Mesoionics.

• Group 4F: Pyridylidenes.

These codes help users to identify the classification of active ingredients more accurately.

However, it should be noted that different subgroup letters do not automatically prove that two products are suitable for resistance management rotation. A judgement must also be made in conjunction with the target pest’s susceptibility, cross-resistance information and current IRAC recommendations.

What Are the Most Common IRAC Groups in Insecticides?

Understanding common groups is the first step in using the IRAC Classification.

Listed below are some representative groups and active ingredients. This table is intended to aid understanding of the classification logic and is not an exhaustive IRAC coding directory.

The specific classification should be based on the current official version of the IRAC. Although active ingredients in different categories may control the same pests, their modes of action, risks of cross-resistance and conditions of use differ.

Why Are Some Active Ingredients in the Same IRAC Group?

Because they share the same or related primary modes of action.

For example, imidacloprid and dinotefuran both belong to Group 4A.

Although they are different active ingredients, both are neonicotinoids that act on nicotinic acetylcholine receptors.

Therefore, when formulating a resistance management programme, one cannot simply assume that switching from imidacloprid to dinotefuran constitutes rotation between independent modes of action.

You may wish to consult Dinotefuran vs Imidacloprid for further details on the differences between these two active ingredients.

How Do You Find an Insecticide’s IRAC Group?

When actually purchasing or using an insecticide, there is no need to memorise all the IRAC codes. It is more important to know the correct method of looking them up.

Step 1: Identify the Active Ingredient

First, check the product label or technical data sheet to find the ‘Active Ingredient’.

Do not simply note down the trade name, as different brands may use the same active ingredient.

If the product is a mixed pesticide, you will also need to identify each active ingredient separately.

Step 2: Check the Official IRAC Classification

Visit IRAC Mode of Action Classification and search for the corresponding Group and Subgroup based on the name of the active ingredient.

When searching, use the current version to avoid relying on outdated classification tables or unverified third-party sources.

Step 3: Check Every Active Ingredient in a Mixture

Suppose a product contains two active ingredients.

You need to look up the IRAC Group for each of the two ingredients separately, rather than simply recording one group.

This helps to determine the composition of the mixture’s mode of action and assess its role in a resistance management programme.

However, it must be emphasised that the fact a mixture contains two different Groups does not automatically mean it is effective in managing resistance. Each active ingredient must possess sufficient activity against the target pests and comply with the relevant conditions of use.

Step 4: Verify the Product Label

IRAC classification is no substitute for the product’s registered label.

Before final use, it is still necessary to confirm:

• Whether the product is authorised for use in the target countries and regions.

• Whether the target crops and pests are covered by the registration.

• The recommended dosage, application interval and maximum number of applications.

• Whether there are any local resistance management requirements.

• Whether specific rotation or application window recommendations need to be followed.

This step is particularly important for the international trade in pesticides. The registered uses and labelling requirements for the same active ingredient may differ from country to country.

How Do IRAC Groups Help Manage Insecticide Resistance?

One of the most important practical uses of IRAC Groups is to help users identify whether the insecticides they are using on a continuous basis rely too heavily on the same mode of action.

When pest populations are repeatedly subjected to selective pressure from the same mechanism of action, individuals with resistance traits may be more likely to survive and reproduce, leading to a decline in the effectiveness of subsequent control measures.

By making judicious use of different yet still effective MoA groups, it is possible to reduce continued reliance on a single mechanism of action and help delay the development of resistance.

Why Changing Brands Is Not Enough

Suppose a farmer uses two different brands of insecticide consecutively.

The first product contains bifenthrin, whilst the second contains deltamethrin.

Although the product brands and active ingredients differ, both belong to IRAC Group 3A.

Therefore, this switch cannot simply be regarded as having achieved rotation between different modes of action.

Similarly, imidacloprid and dinotefuran both belong to Group 4A; they cannot be deemed suitable as independent resistance management rotation partners merely on the basis of their different active ingredients.

If you require further information on how to sequence applications between different modes of action, please refer to Why Rotate Pesticide Modes of Action?.

Can Different IRAC Groups Have Cross-Resistance?

Yes.

Different IRAC groups are typically used to distinguish between different modes of action, but this does not mean that cross-resistance between them is absolutely impossible.

For example, certain metabolic resistance mechanisms may affect insecticides belonging to multiple groups of modes of action.

Therefore, even if two active ingredients belong to different groups, it cannot automatically be assumed that the second product will certainly control pest populations that have already developed resistance to the first product.

Decisions regarding actual rotation should be based on the target pest, local resistance monitoring, IRAC guidelines and product labels.

What Do IRAC Groups Not Tell You?

IRAC classification is very useful, but it does not answer all product selection questions.

For example, abamectin belongs to IRAC Group 6, but the IRAC code does not directly indicate whether a particular abamectin product acts by contact or what its translocation properties within plant tissues are.

These are distinct product attributes.

You can find out more at Is Abamectin Contact or Systemic? to understand the difference between Mode of Action and Contact / Systemic.

Therefore, making an accurate assessment of a product requires combining the IRAC classification with the product label, active ingredient data, target pests and local resistance information.

What Should Insecticide Buyers Check?

For pesticide importers, distributors and brand owners, IRAC Groups can also be used to analyse whether a product portfolio is overly concentrated on certain modes of action.

Suppose a market already has several different brands of insecticides, but they rely primarily on the same IRAC Group. In that case, the product portfolio may still be relatively limited in terms of modes of action.

This does not mean that these products lack commercial value; rather, it indicates that during procurement and product planning, it is necessary to further ascertain whether their actual pest control applications overlap and whether suitable alternative modes of action are available.

For procurement teams, a more sensible approach is to first identify the key crops and target pests, then review the active ingredients and IRAC groups of existing products, and finally determine which genuinely useful products need to be added.

The value of a product portfolio lies not in the number of trade names it contains, but in its ability to meet the pest control needs of the target market and in having a sensible distribution of modes of action.

Frequently Asked Questions

What Does IRAC Group 4A Mean?

IRAC Group 4A refers to neonicotinoid insecticides, which belong to the class of nicotinic acetylcholine receptor competitive modulators. For example, imidacloprid and dinotefuran both belong to this group.

Are two insecticides in the same IRAC Group interchangeable?

Not necessarily. Even if two products belong to the same group, their spectrum of activity, formulation, registered crops and actual performance may differ. Furthermore, cross-resistance may exist between products within the same group, so one cannot assume they are interchangeable based solely on the group code.

Can I Rotate Insecticides From Different IRAC Groups?

Rotating between products from different Groups may be a sound resistance management strategy provided that both products are effective against the target pests, there are no known issues of cross-resistance, and they comply with label instructions and local guidelines. However, a difference in Group does not automatically guarantee that rotation will be effective.

Does a Different Brand Mean a Different IRAC Group?

No. A single active ingredient may be marketed under multiple brand names, but its IRAC Group does not change simply because the brand name changes. Changing the brand, concentration or formulation does not equate to changing the mode of action.

Does an IRAC Group Number Indicate Insecticide Toxicity?

No, it does not. The IRAC Group is a classification based on mode of action; it is not a ranking of toxicity, safety or efficacy. The risks associated with a product and its usage requirements must be assessed based on the label, the properties of the active ingredient, exposure conditions and relevant regulations.

How Often Should Insecticide IRAC Groups Be Rotated?

There is no standard interval applicable to all pests and insecticides. Specific rotation schedules must take into account pest generations, crop growth stages, application windows, the risk of resistance in target pests, and local IRAC guidelines.

Choose Insecticides With a Clear Understanding of Their IRAC Groups

Understanding IRAC groups can help you identify the modes of action of insecticides, avoid mistaking different brands for different resistance management options, and provide a more reliable technical basis for product procurement and field control.

For growers, the focus is on developing a sound application plan based on the target pests and local resistance risks.

For importers, distributors and brand owners, the focus is on confirming a product’s active ingredients, IRAC Group, target crops, pest control scope and registration requirements, whilst also checking whether there is excessive overlap in modes of action within the existing product portfolio.

If you are planning a new insecticide product portfolio, it is advisable to first identify the target countries, major crops, key pests and existing active ingredients, before assessing the types of products required to fill any gaps.

You can also submit your target markets and procurement requirements via POMAIS Contact Us to discuss suitable active ingredients, formulation types and product portfolios in further detail.

The true value of IRAC Groups lies not in memorising all the numbers, but in helping you understand the mode of action of each insecticide and applying this information to make more informed product choices and manage resistance in the long term.