Which of the following is synonymous with a pesticide in the context of insect management?

Insecticide is synonymous with a pesticide in the context of insect management because it refers specifically to substances designed to kill or control insects. Pesticides are a broader category that encompasses various substances used to manage pests, including those targeting insects (insecticides), weeds (herbicides), and rodents (rodenticides). Thus, while all insecticides are pesticides, not all pesticides are insecticides, making the term insecticide the correct choice for insect management.

Other options like rodenticide, herbicide, and plant hormone serve different purposes—rodenticides for rodent control, herbicides for weed management, and plant hormones for influencing plant growth—so they do not fit the context of managing insects.