How are pests classified?

Pests are primarily classified into five major categories based on the type of damage they cause.

The first category is public health pests, which transmit diseases or affect human health.

Typical examples include mosquitoes (which transmit malaria and dengue fever), flies (which mechanically transmit cholera and dysentery), and cockroaches (which carry pathogens like *Salmonella* and trigger allergies and asthma).

The second category is agricultural pests, which damage crops and forests—such as locusts, aphids, and bollworms—causing 10%–30% global crop losses annually.

The third category is stored-product pests, which infest stored grain and food, such as rice weevils, lesser grain borers, and Indian meal moths.

They not only cause weight loss by direct feeding but also contaminate food with their excrement and body parts.

The fourth is structural pests, which damage buildings and wood structures, represented by termites.

Global economic losses from termites exceed $40 billion annually.

The fifth category is nuisance pests, which do not transmit serious diseases but affect quality of life, such as silverfish, beetles, bed bugs, and centipedes.

Different classifications dictate different control strategies and priorities—for instance, structural pests like termites require immediate professional intervention, whereas nuisance pests like silverfish can often be managed through environmental control.