Associate Certified Entomologist (ACE) Practice Exam

What is an example of a phenylpyrazole commonly used in pest control?

1. Chlorfenapyr

2. Fipronil

3. Abamectin

4. Emamectin

The correct answer is: Fipronil

Fipronil is a well-known phenylpyrazole insecticide widely used in pest control. Its mechanism of action involves disrupting the normal functioning of the insect's nervous system by blocking gamma-aminobutyric acid (GABA) receptors and glutamate-gated chloride channels. This leads to uncontrolled neuronal activity, ultimately resulting in the death of the targeted pests. Fipronil is effective against a broad spectrum of insects, including ants, cockroaches, termites, and fleas. Its selective toxicity allows it to be effective in various formulations for both indoor and outdoor applications, making it a popular choice among pest management professionals. The other choices listed, while effective pesticides, belong to different chemical classes. Chlorfenapyr is a pro-insecticide that acts by disrupting energy production in insects. Abamectin is an avermectin, which primarily affects the nervous system and is more commonly used for its acaricidal properties. Emamectin is a derivative of abamectin, intended mainly for use on agricultural pests. Each of these chemicals has its own mode of action and application area but does not fall under the phenylpyrazole group like fipronil does.