Associate Certified Entomologist (ACE) Practice Exam

Which class of insecticides is often used as baits for slow-acting effects?

1. Neonicotinoids

2. Spinosyns

3. Phenylpyrazoles

4. Pyrethroids

The correct answer is: Phenylpyrazoles

The class of insecticides that is often used as baits for slow-acting effects is phenylpyrazoles. These insecticides affect the insect's nervous system by disrupting the normal functioning of GABA (gamma-aminobutyric acid) receptors, which are crucial for the regulation of neuronal activity. Their slow-acting nature allows insects to consume the bait and return to their hiding places before the effects manifest, leading to a higher chance that other insects will also consume the bait and be affected. This characteristic makes phenylpyrazoles particularly effective in controlling pest populations over time, as they help to eliminate not only the initially targeted insects but also those that come into contact with them later. Neonicotinoids, while effective, typically act more rapidly and don't possess the same baiting strategy for gradual effects. Spinosyns also act fairly quickly and are more commonly used as contact insecticides rather than for slow baiting effects. Pyrethroids, known for their fast-acting knockdown capability, are less favorable for this purpose as they work immediately upon contact or ingestion, thus not allowing for the slow-acting strategy seen with phenylpyrazoles.