There are some insects that are useful to people. Bees for example, make honey. The larvae of some moths make silk, and in some parts of the world; people actually eat insects. However in some cases, insects and bugs can be harmful to people, and thus earned the designation of pest. For example, some insect pests are parasites, such as lice, mosquitoes and bed bugs, and are known to spread disease.
In other instances, the insect pests do not harm people directly. For example, termites and some beetles will consume wood, and thus create an insect control problem, by causing extensive structural damage; to buildings and homes. Furthermore, some common insects, such as the grasshopper, will eat and destroy agricultural products; that are intended for human consumption.