Insecticides mode of action in relation to their toxicity to non-target organisms

The mode of action of insecticides is responsible for their higher or lower toxicity to non-target organisms. However, the large variations in susceptibility among different animal taxa indicate that certain biochemical traits particular to a group of organisms are responsible for a specific level of sensitivity. A review of toxicity data to non-target organisms is presented here. Aquatic arthropods are most susceptible to all types of insecticides because they share many physiological features with the target insects. Other aquatic organisms, such as fish and amphibians, are very sensitive to broad-spectrum neurotoxic and respiratory inhibitor insecticides, but not so much to selective insecticides such as IGRs and stomach poisons. Terrestrial vertebrates are also sensitive to most neuro-toxicants and respiratory inhibitors, with the exception of those insecticides derived from natural toxins produced by plants or fungi (e.g. pyrethroids, neonicotinoids, avermectins, spinosad), which appear to have little or no toxicity in birds and mammals.