Which two types of insecticides are considered non-repellent?

In the context of termite control and insecticide application, non-repellent insecticides play a crucial role in effectively managing pest populations. Neonicotinoids and phenylpyrazole are well-known classes of insecticides that do not repel insects. Instead, they work by interfering with the nervous system of pests, leading to their death without immediately causing them to avoid treated areas. This lack of repellency allows insects to come into contact with the insecticide, thus increasing the likelihood of exposure and effectiveness.

Neonicotinoids function by mimicking the action of the neurotransmitter acetylcholine, binding to nicotinic receptors and causing paralysis. Phenylpyrazole disrupts the normal function of the nervous system by blocking the passage of chlorine ions through the GABA-gated channels, also leading to paralysis and death. These mechanisms are particularly advantageous in termite control, as termites are social insects that can share the insecticide with colony members, enhancing overall efficacy.

The other options consist of insecticides and materials that may have repellent properties or different modes of action. For instance, pyrethroids and organophosphates are known for their quick knockdown effects but can also induce avoidance behaviors in pests, which diminishes their effectiveness in