What type of pesticide removes moisture from a pest, leading to its death?

The correct answer is a desiccant. Desiccants are substances that promote drying by absorbing moisture, and when used as pesticides, they target pests by removing the moisture necessary for their survival. This loss of moisture leads to dehydration, ultimately resulting in the death of the pest.

For instance, common desiccant materials, such as diatomaceous earth or silica gel, can be used against insects by disrupting their exoskeletons, allowing moisture to escape. This action is critical in effectively controlling populations of insects that rely on moisture to maintain their physiological functions.

Insecticides, on the other hand, are specifically designed to kill or repel insects, usually through toxic effects rather than through moisture removal. Fungicides target fungal growth, and herbicides are effective against plants. Both fungicides and herbicides function through mechanisms different from that of desiccants, making it clear why they would not be suitable for moisture removal and pest control in this context.