ENVS 3020 Lecture Notes - Lecture 5: Pesticide Resistance, Chordotonal Organ, Cypermethrin
12 Jul 2020
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Document Summary
Insecticides may be classified in various manners including by chemical structure, toxicity, insect stage targeted and mode of action (moa). We will focus on the latter and whereas with herbicides there were three relatively common classification systems there is only one for insecticides, which has been developed by the insecticide resistance action committee (irac). The irac scheme separates insecticides into five main categories based on their moa. The first four include about 32 groups with a known moa and target either the nerve-muscle system, growth and development, the insect midgut or respiration. The fifth category has about five groups of insecticides with an unknown or non-specific. Moa that are mostly categorized by the source of the insecticide, for example, bacterial, botanical or fungal compounds. As an example, the synthetic insecticide cypermethrin is in group 3 (sodium channel modulators) and subgroup a (pyrethroids/pyrethrins). Insecticides that affect the nervous system account for nearly half of all known insecticide modes of action.
