A pest is an annoying creature who may pose some threat to a human, or they are, in general, harmful beyond the economic threshold level. This pest can include everything from a mouse or rat to bed bugs, which are far less appealing.
Pest control methods should be applied when the pest population reaches a specific upper limit level. Any killing agent that kills pests is called a pesticide. On the other hand, an insect is something like a spider or an ant.
Generally, when there are ants, they all come together, and they are drawn to sweet or sticky matter, which is why they tend to hang around. An insect body can be divided into three parts: the head, thorax, and abdomen, and insects also have antennae.