Difference Between Pest and Insect

Pest vs Insect

There is some relationship between pests and insects as some pests are insects. However, all insects are not pests; some of them are beneficial organisms to  the human being. The pest group includes vertebrates, invertebrates, and plants. This  article intends to compare these two organisms, the pests and insects.


A pest is a competitor of the human being. The term pest can be defined as, any creature or organism which causes harm to human being, beyond the economical threshold level. Economical threshold level is the maximum level of pest population that can be tolerated without economical loss. Pest group includes insects, ticks, mites, nematodes, birds, mammals and plants. Invertebrate pests include parasites (lice, bed bugs), disease transmitting agents (mosquitoes, thrips and flies), and damage causing agents (termites).

Any killing agent that kills pests is called a pesticide. Other than using pesticides, there are several alternative methods such as biological pest control, cultural practices, traps, repellent etc.


Do you know that the insects have been present for about 350 million years, and humans for only 130,000 years? Insects are a class of arthropods. They constantly interact with the human life, either as pests or as beneficial organisms. In addition, there are some insect species that are an important component of the ecosystems. Since insects can tolerate adverse environmental conditions, they are widely distributed all over the world.

Insect body can be divided in to three parts. Those are head, thorax and abdomen. Characteristic features of insects include the presence of one pair of antennae, two pairs of wings (a few insects such as ants don’t have wings, and some insects such as flies only have one pair of wings), and three pairs of segmented legs. Metamorphism is the common feature of all insects. There are two types of metamorphosis – incomplete and complete. They have exoskeletons, which consists of chitins. Any killing agent that is usesd to kill insects is called as insecticide. Pests that are insects can be biologically controlled by another type of insects. Those can be either parasite (group hymenoptera) or predators (group coccinellidae and carabidae) of the insect pest. Also, insects are important in pollination and environmental sustainability. Some insects such as moths are pest at the larval stage and beneficial as pollinators at the adult stage. Entomology is the branch of Zoology concerned with the study of insects.

What is the difference between Pest and Insect?

• Pests are organisms which cause harm to the human being, beyond economical threshold level. Pest controlling methods should be applied when the pest population reaches the economical threshold level. Pests include invertebrates, vertebrates and plants. Some pests are insects but, all insects are not pests.

• Even though, all pests are harmful to the human being, some insects are beneficial.

• Killing agents that kill pests are pesticides, and killing agents that, kill insects are insecticides.

• Some environmental friendly methods are available other than insecticides and pesticides.

• Insects belong to phylum Arthropoda. Characteristic features of insects include one pair of antennae, two pairs of wings, and three paisr of legs.

• Metamorphism is a common feature of all insects. There are two types of metamorphosis – incomplete and complete.

• Insect body can be divided in to three parts – head, thorax, and abdomen. Also, they have an exoskeleton, which is made out of chitin.

• There are two types of biological control agents of insects. They are parasitic insects and predator insects.

• Some insects Such as moths are pests at the larval stage and become beneficial organisms at the adult stage.