What is a chemical formulated to kill insects referred to as?

A chemical formulated specifically to kill insects is referred to as a pesticide. The term "pesticide" is a broad category that includes any substance used to control, deter, or eliminate pests, which encompasses insects, weeds, fungi, and other unwanted organisms.

While "insecticide" refers specifically to chemicals that target insects, it is a subset of pesticides. Therefore, while insecticides fall under the broader umbrella of pesticides, the correct response to this question highlights the comprehensive nature of the term "pesticide," which is applicable to more than just insects.

The other options relate to different classes of chemicals: fungicides are used to kill fungi, herbicides are designed to kill weeds or plants, and insecticides target insects directly. This distinction emphasizes the importance of understanding the various types of pest management chemicals and their specific applications.