IRAC Mode of Action Classification Scheme (Edition 11.5)

A complete set of vocabulary flashcards covering the IRAC Insecticide, Acaricide, and Nematicide Mode of Action Classification Scheme, resistance management principles, sub-groups, and pest targets.

Insecticide Resistance Action Committee (IRAC)

A technical group of CropLife International formed in 1984 to provide a coordinated crop protection industry response to prevent or delay the development of resistance in insect, mite, and nematode pests.

Resistance to Insecticides

A heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendation for that pest species.

Sub-groups (IRAC Classification)

Distinct chemical classes believed to have the same MoA but different enough in chemical structure or mode of interaction with the target protein that the chance of selection for either metabolic or target-site cross-resistance is reduced compared to close analogs.

Acetylcholinesterase (AChE) Inhibitors (Group 1)

Mode of Action group targeting acetylcholinesterase, comprising Subgroup 1A (Carbamates) and Subgroup 1B (Organophosphates).

GABA-gated Chloride Channel Blockers (Group 2)

Mode of Action group blocking GABA-gated chloride channels, including Subgroup 2A (Cyclodiene Organochlorines) and Subgroup 2B (Phenylpyrazoles / Fiproles).

Sodium Channel Modulators (Group 3)

Mode of Action group modulating sodium channels, divided into Subgroup 3A (Pyrethroids, Pyrethrins) and Subgroup 3B (DDT, Methoxychlor).

nAChR Competitive Modulators (Group 4)

Nicotinic acetylcholine receptor competitive modulators including Neonicotinoids (4A), Nicotine (4B), Sulfoximines (4C), Butenolides (4D), Mesoionics (4E), and Pyridylidenes (4F).

nAChR Allosteric Modulators - Site I (Group 5)

Allosteric modulators acting at Site I of the nicotinic acetylcholine receptor, exemplified by Spinosyns (Spinetoram and Spinosad).

GluCl Allosteric Modulators (Group 6)

Glutamate-gated chloride channel allosteric modulators, exemplified by Avermectins and Milbemycins (such as Abamectin, Emamectin benzoate, Lepimectin, and Milbemectin).

Juvenile Hormone Receptor Modulators (Group 7)

Insect growth regulators modulating juvenile hormone receptors, including Subgroup 7A (Juvenile hormone analogues), 7B (Fenoxycarb), and 7C (Pyriproxyfen).

Chordotonal Organ TRPV Channel Modulators (Group 9)

Modulators of chordotonal organ TRPV channels, including Subgroup 9B (Pyridine azomethine derivatives) and Subgroup 9D (Pyropenes).

Microbial Disruptors of Insect Midgut Membranes (Group 11)

Biopesticides disrupting midgut membranes, including Bacillus thuringiensis and its insecticidal proteins (11A) and Bacillus sphaericus (11B).

Inhibitors of Chitin Biosynthesis Affecting CHS1 (Group 15)

Benzoylurea compounds (e.g., Novaluron, Lufenuron, Diflubenzuron) that inhibit chitin biosynthesis affecting chitin synthase 1 (CHS1).

Ecdysone Receptor Agonists (Group 18)

Diacylhydrazine active ingredients (e.g., Chromafenozide, Halofenozide, Methoxyfenozide, Tebufenozide) that act as ecdysone receptor agonists.

Ryanodine Receptor Modulators (Group 28)

Diamide insecticides (such as Chlorantraniliprole, Cyantraniliprole, Cyclaniliprole, Flubendiamide, and Tetraniliprole) targeting ryanodine receptors.

Sub-group 3B Usage Note

Because DDT is no longer used in agriculture, Subgroup 3B is only applicable for the control of human disease vectors such as mosquitoes.

Sub-groups 4A-4F Cross-Resistance Note

Although these compounds are believed to have the same target site, current evidence indicates that the risk of metabolic cross-resistance between subgroups 4A, 4B, 4C, 4D, 4E, and 4F is low.

Nematicide Group N-1

Acetylcholinesterase (AChE) inhibitors used as nematicides, divided into Carbamates (N-1A) like Aldicarb and Oxamyl, and Organophosphates (N-1B) like Fosthiazate and Fenamiphos.

Nematicide Group N-3

Mitochondrial complex II electron transport inhibitors (Succinate-coenzyme Q reductase) used as nematicides, exemplified by Cyclobutrifluram and Fluopyram.

Root-knot Nematode J2

Microscopic view of Meloidogyne species juvenile stage 2 (J2) and egg.

Potato Cyst Nematode (PCN)

Plant-parasitic cyst nematode showing cyst, eggs, and J2 juveniles.

Lepidoptera Larva

Caterpillar stage of Lepidoptera targeted by midgut disruptors, chitin biosynthesis inhibitors, and nerve and muscle insecticides.

Whitefly

Sap-sucking insect pest belonging to Hemiptera controlled by various MoA groups including neonicotinoids, ketoenols, and chordotonal organ modulators.

Acarid (Mite)

Mite pest targeted by dedicated acaricides including METI acaricides, growth inhibitors affecting CHS1, and mitochondrial complex electron transport inhibitors.