A pest's life cycle refers to its complete developmental process from egg to adult, and can be divided into two major types.
Holometabola (complete metamorphosis) involves four stages—egg, larva, pupa, adult—where the larva and adult differ completely in form and habits.
Pests with complete metamorphosis include flies, beetles (stored-product pests like rice weevils), moths (clothes moths), fleas, bees, and wasps.
Hemimetabola (incomplete metamorphosis) involves three stages—egg, nymph, adult—where the nymph resembles the adult but is smaller and wingless, gradually growing through molting.
Pests with incomplete metamorphosis include cockroaches, bed bugs, termites, aphids, and locusts.
Understanding a pest's life cycle is crucial for control.
For instance, using insect growth regulators (IGRs) targets the molting or pupation stages to disrupt development.
Some pesticides are effective against adults but not eggs, so treatment timing and frequency must be determined based on the life cycle.
This is why bed bug treatments often require 2–3 applications spaced about 2 weeks apart, to cover newly hatched nymphs emerging from eggs.