Associate Certified Entomologist (ACE) Practice Exam

What is the mode of action for oxadiazines?

1. Block sodium channels in nerve cells

2. Disrupt protein synthesis

3. Inhibit enzyme activity

4. Prevent DNA replication

The correct answer is: Block sodium channels in nerve cells

The mode of action for oxadiazines primarily revolves around their ability to block sodium channels in nerve cells. This mechanism disrupts the normal function of the nervous system in target insects, leading to paralysis and eventual death. Sodium channels are critical for the generation and propagation of action potentials in neurons; when these channels are blocked, it interferes with the transmission of nerve impulses. This action makes oxadiazines particularly effective as insecticides, especially against pests that rely on their nervous system for movement and other essential functions. Understanding the significance of this action helps contextualize the other options. Disrupting protein synthesis is typically associated with different classes of insecticides that work by targeting ribosomal functions, while inhibiting enzyme activity relates to modes of action seen in organophosphates and carbamates. Preventing DNA replication is another mechanism associated with a separate group of pesticides, such as certain fungal and herbicidal substances. Each of these processes is crucial in their own right, but the specific targeting of sodium channels is what defines the unique effectiveness of oxadiazines in pest control strategies.